Imaging apparatus and endoscope apparatus with selectable wavelength ranges

ABSTRACT

The imaging apparatus and endoscope apparatus comprise an image forming optical system forming the image of an object to be imaged. An imaging device has a sensitivity to a wavelength range ranging from a visible range to a range other than the visible range and converts the image formed by the image forming optical system to an electric signal. A wavelength range divides device dividing the wavelength range ranging from the visible range to the range other than the visible range into a plurality of wavelength ranges. A selects device selecting at least one wavelength range from among the wavelength ranges divided by the wavelength range dividing device. A signal processing device processes the output signals of the imaging device in response to the selected wavelength ranges so as to be video signals.

This is a division, of application Ser. No. 128,118 filed on Nov. 30,1987 and continued on Dec. 11, 1989 as Ser. No. 449,436 now U.S. Pat.No. 4,974,076.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an imaging apparatus wherein the observingwavelength range can be selected in response to an observed object andan endoscope apparatus using the same.

2. Related Art Statement

Recently, there are suggested various electronic endoscopes wherein asolid state imaging device such as a charge coupled device (CCD) is usedfor an imaging means.

The electronic endoscope has advantages because the resolution is higherthan in a fiberscope, it is easy to record and reproduce picture imagesand treatment of picture images such as enlargement and the comparisonof two picture images are easy.

When observing an object by using an imaging device as of the abovementioned electronic endoscope and particularly when distinguishing anaffected part and normal part from each other within a living body, itis necessary to sense (recognize) a delicate color tone difference.However, in case the difference of the color tone in the observedposition is delicate, a high degree of knowledge and experience will berequired to sense this delicate difference, a long time will be requireduntil it is detected and it has been difficult to always properly judgethe difference even if cautious forces are concentrated while sensing.

In order to cope with this situation, for example, in the gazette ofJapanese Patent Laid Open No. 3033/1981, there is disclosed a techniquewherein, by noting that the difference of the color tone may be large ina range other than the visible range as, for example, an infraredwavelength range, a spectral light having at least one infraredwavelength range is led in time series to illuminate an object to beobserved. The reflected light from the object is imaged in a solid stateimaging device and is converted to an electric signal. The electricsignal is processed in response to the wavelength range and a pictureimage of the wavelength range is displayed by a specific color signal.According to this related art example, the invisible informationobtained in the infrared wavelength range can be converted to visibleinformation and, for example, the affected part and normal part can bequickly and easily discriminated from each other.

However, in the above mentioned related art example, since the observingwavelength range is fixed, for example, there are disadvantages that,when infrared light is utilized, no picture image of a general visiblerange will be obtained, it will be difficult to compare both pictureimages and there will be no effect on an observed object characteristicin another wavelength range.

Also, for example, in the gazette of Japanese Patent Laid Open No.139237/1984, there is disclosed a technique that a plurality of pictureimages are taken by passing a fluorescence generated from a living bodyin response to an excited light radiation through a plurality of typesof band pass filters and respectively different color tones are allotedto the density grade differences of the respective picture images toform respective quasi color picture images.

However, in this related art example, the density difference can bediscriminated but the color tone difference can not be discriminated.

OBJECTS AND SUMMARY OF THE INVENTION

An object of the present invention is to provide an imaging apparatusand endoscope apparatus whereby visible information can be obtained byselecting a suitable wavelength range in response to an object to beobserved.

Another object of the present invention is to provide an imagingapparatus and endoscope apparatus whereby the color tone differences, inthe respective positions of an observed object which are difficult todiscriminate in a picture image in a general visible range, can beeasily detected.

A further object of the present invention is to provide an imagingapparatus and endoscope apparatus whereby the state of veins runningbelow a mucous membrane and the penetrating range of a disease can beobserved.

A further object of the present invention is to provide an imagingapparatus and endoscope apparatus whereby a color distribution in aliving body tissue can be detected.

Each of the imaging apparatus and endoscope apparatus of the presentinvention comprises an image forming optical system forming an image ofan object to be imaged, an imaging device having a sensitivity in awavelength range ranging from a visible range to another range otherthan the visible range and converting the image formed by the abovementioned image forming optical system to an electric signal, awavelength range dividing device dividing the wavelength range rangingfrom the visible range to the range other than the visible range into aplurality of wavelength ranges, a selecting device selecting at leastone wavelength range from among the wavelength ranges divided by theabove mentioned wavelength range dividing device and a signal processingdevice processing the output signal of the above mentioned imagingdevice to be a video signal in response to the above mentioned selectedwavelength range.

The other features and advantages of the present invention will becomeapparent enough with the following explanation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 6 relate to the first embodiment of the present invention.

FIG. 1 is a block diagram showing the formation of an imaging apparatus.

FIG. 2 is a side view showing an entire electronic endoscope apparatus.

FIG. 3 is an explanatory view showing a band switching filter.

FIG. 4 is an explanatory view showing a rotary filter.

FIG. 5 is an explanatory view showing the transmitted wavelength bandsof the respective filters of the band switching filter.

FIG. 6 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the rotary filter.

FIGS. 7 and 8 are block diagrams showing imaging apparatus relating tothe second embodiment of the present invention.

FIGS. 9 to 11 relate to the third embodiment of the present invention.

FIG. 9 is a block diagram showing an imaging apparatus.

FIG. 10 is an explanatory view showing a rotary filter.

FIG. 11(A) is a timing chart showing a timing of an illuminating light.

FIG. 11(B) is a timing chart showing a timing of selecting a signal atthe time of selecting a visible band.

FIG. 11(C) is a timing chart showing a timing of selecting a signal atthe time of selecting an ultraviolet band.

FIG. 11(D) is a timing chart showing a timing of selecting a signal atthe time of selecting an infrared band.

FIG. 11(E) is a timing chart showing a timing of selecting wavelengthranges of G, R and IR1.

FIGS. 12 and 15 relate to the fourth embodiment of the presentinvention.

FIG. 12 is a block diagram showing an imaging apparatus.

FIG. 13 is an explanatory view showing a rotary filter.

FIG. 14(A) is a timing chart showing a timing when respective filters ofa rotary filter are interposed in an illuminating light path.

FIG. 14(B) is a timing chart showing a timing when a lamp emits a lightat the time of selecting a visible band.

FIG. 14(C) is a timing chart showing a timing when a lamp emits a lightat the time of selecting an infrared band.

FIG. 14(D) is a timing chart showing a timing when a lamp emits a lightat the time of selecting an ultraviolet band.

FIG. 14(E) is a timing chart showing a timing when a lamp emits a lightat the time of selecting wavelength ranges of G, IR2 and IR3.

FIG. 14(F) is a timing chart showing a timing when a lamp emits a lightat the time of selecting a wavelength range of B.

FIG. 15 is an explanatory diagram showing a spectral characteristicvariation of blood by mixing in ICG.

FIGS. 16 to 18 relate to the fifth embodiment of the present invention.

FIG. 16 is an explanatory view showing the formation of an endoscopeapparatus.

FIG. 17 is an explanatory view showing a rotary filter.

FIG. 18(A) is a timing chart showing a timing when respective filters ofa rotary filter are interposed in an illuminating light path.

FIG. 18(B) is a timing chart showing a timing when a lamp emits a lightat the time of selecting a visible band.

FIG. 18(C) is a timing chart showing a timing when a lamp emits a lightat the time of selecting an infrared band.

FIG. 18(D) is a timing chart showing a timing when a lamp emits a lightat the time of selecting an ultraviolet band.

FIG. 18(E) is a timing chart showing a timing when a lamp emits a lightat the time of selecting wavelength ranges of G, IR2 and IR3.

FIG. 18(F) is a timing chart showing a timing when a lamp emits a lightat the time of selecting a wavelength range of B.

FIGS. 19 to 21 relate to the sixth embodiment of the present invention.

FIG. 19 is an explanatory view showing the formation of an imagingapparatus.

FIG. 20 is an elevation of a band switching mirror.

FIG. 21 is an explanatory diagram showing reflection characteristics ofrespective mirrors of the band switching mirror.

FIG. 22 is an explanatory view showing a modification of a light sourcepart in the sixth embodiment.

FIG. 23 is an elevation of a band switching mirror in a modification ofthe sixth embodiment.

FIGS. 24 and 25 relate to the seventh embodiment of the presentinvention.

FIG. 24 is an explanatory view showing a light source part.

FIG. 25 is an explanatory view showing a rotary filter.

FIGS. 26 to 29 relate to the eighth embodiment of the present invention.

FIG. 26 is a block diagram showing the formation of an imagingapparatus.

FIG. 27 is an explanatory view showing a rotary filter.

FIG. 28 is an explanatory diagram showing transmitting characteristicsof respective filters of a rotary filter.

FIG. 29 is an explanatory diagram showing absorption spectra ofrespective colors of a living body.

FIGS. 30 to 32 are explanatory views showing modifications of the eighthembodiment.

FIGS. 33 and 34 relate to the ninth embodiment of the present invention.

FIG. 33 is an explanatory view showing the formation of a CCD (chargecoupled device).

FIG. 34(A) is an explanatory view showing a shutter.

FIG. 34(B) is an explanatory view showing another state of the shutter.

FIGS. 35 to 38 relate to the tenth embodiment of the present invention.

FIG. 35 is a block diagram showing the formation of an imagingapparatus.

FIG. 36 is an explanatory view showing the formation of a CCD with anelectronic shutter.

FIGS. 37(A), 37(B) and 37(C) are explanatory views showing respectiveoperating modes of electronic shutters.

FIG. 38(A) is a timing chart showing timings when respective filters ofa rotary filter are interposed in an illuminating light path.

FIG. 38(B) is a timing chart showing an operating mode of a CCD.

FIG. 38(C) is a timing chart showing an operation of a light receivingpart of a CCD.

FIG. 39 is an explanatory view showing the formation of an endoscopeapparatus relating to the eleventh embodiment of the present invention.

FIGS. 40 to 44 relate to the twelfth embodiment of the presentinvention.

FIG. 40 is a block diagram showing an imaging apparatus.

FIG. 41 is an explanatory view showing a band limiting filter.

FIG. 42 is an explanatory diagram showing the transmittingcharacteristics of respective filters of a band limiting filter.

FIG. 43 is an explanatory view of a rotary filter.

FIG. 44 is an explanatory diagram showing the transmittingcharacteristics of respective filters of the rotary filter.

FIG. 45 is an explanatory diagram showing the transmittingcharacteristics of respective filters of a modification of the rotaryfilter in the twelfth embodiment.

FIGS. 46 and 47 are explanatory views showing modifications of the bandlimiting filter in the twelfth embodiment.

FIGS. 48 to 50 related to the thirteenth embodiment of the presentinvention.

FIG. 48 is an explanatory diagram showing a light source part.

FIG. 49 is an explanatory diagram showing the transmittingcharacteristic of a band limiting filter of a narrow band.

FIG. 50 is an explanatory diagram showing the difference between thespectral characteristics of blood in which ICG is mixed and blood inwhich ICG is not mixed.

FIG. 51 is an explanatory diagram showing a light source part in amodification of the thirteenth embodiment.

FIG. 52 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the rotary filter in thefourteenth embodiment of the present invention.

FIGS. 53 and 54 relate to the fifteenth embodiment of the presentinvention.

FIG. 53 is an explanatory view showing a rotary filter.

FIG. 54 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the rotary filter.

FIGS. 55 to 58 relate to the sixteenth embodiment of the presentinvention.

FIG. 55 is an explanatory view showing a band limiting filter.

FIG. 56 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the band limiting filter.

FIG. 57 is an explanatory view showing a rotary filter.

FIG. 58 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the rotary filter.

FIG. 59 is an explanatory view showing the formation of an endoscopeapparatus relating to the seventeenth embodiment of the presentinvention.

FIGS. 60 to 65 relate to the eighteenth embodiment of the presentinvention.

FIG. 60 is a block diagram showing the formation of an imagingapparatus.

FIG. 61 is an explanatory diagram showing the light emittingcharacteristic of a light source.

FIG. 62 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of a band limiting filter.

FIG. 64 is an explanatory view showing a color filter.

FIG. 65 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the color filter.

FIG. 66 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of a color filter relating tothe nineteenth embodiment of the present invention.

FIG. 67 is an explanatory diagram showing a light source part in thetwentieth embodiment of the present invention.

FIG. 68 is an explanatory diagram showing a light source part in amodification of the twentieth embodiment.

FIG. 69 is an explanatory diagram, showing the transmittingcharacteristic of a band limiting filter of a narrow band in thetwenty-first embodiment of the present invention.

FIGS. 70 to 72 relate to the twenty-second embodiment of the presentinvention.

FIG. 70 is an explanatory view showing a band limiting filter.

FIG. 71 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of the band limiting filter.

FIG. 72 is an explanatory diagram showing the transmittingcharacteristics of the respective filters of a rotary filter.

FIG. 73 is an explanatory diagram showing an endoscope apparatusrelating to the twenty-third embodiment of the present invention.

FIGS. 74 to 79 relate to the twenty-fourth embodiment of the presentinvention.

FIG. 74 is a block diagram showing the formation of an imagingapparatus.

FIG. 75 is an explanatory diagram showing a color separating filter.

FIG. 76 is an explanatory diagram showing the transmittingcharacteristics of respective filters.

FIG. 77 is an explanatory diagram showing the transmittingcharacteristic of a filter interposed in an observing light path.

FIG. 78 is an explanatory diagram showing the transmittingcharacteristic of a visible light transmitting filter.

FIG. 79 is an explanatory diagram showing the transmittingcharacteristic of a near infrared band pass filter.

FIGS. 80 to 82 relate to the twenty-fifth embodiment of the presentinvention.

FIG. 80 is a block diagram showing the formation of an imagingapparatus.

FIG. 81 is an explanatory view showing a rotary filter.

FIG. 82 is an explanatory diagram showing the transmittingcharacteristics of respective filters of the rotary filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:

The first embodiment of the present invention is shown in FIGS. 1 to 6.

The imaging apparatus of this emobiment is applied to as electronicendoscope 1 as is shown, for example, in FIG. 2. In this electronicendoscope 1, a large diameter operating part 3 is connected to the rearend of an elongated, for example, flexible insertable part 2. A flexiblecable 4 is extended sidewise from the rear end part of the abovementioned operating part 3 and is provided at the tip with a connector5. The above mentioned electronic endoscope 1 is to be connected throughthe above mentioned connector 5 to a control apparatus in which lightsource part and video signal processing part are built. Further, a colorCRT monitor as a displaying means is to be connected to the abovementioned control apparatus 6.

A rigid tip part 9 is provided on the tip side of the above mentionedinsertable part 2 and a curvable curve part 10 is provided on the rearside adjacent to this tip part 9. The above mentioned curve part 10 canbe curved in the horizontal and vertical directions by rotating acurving knob 11 provided on the above mentioned operating part 3. Aninserting port communicating with a forceps channel provided within theabove mentioned insertable part 2 is provided in the above mentionedoperating part 3.

An imaging apparatus 21 of this embodiment is formed as shown in FIG. 1.A light source part 22 having a light source 24 is provided within theabove mentioned control apparatus 6. The above mentioned light source 24emits lights of wavelengths in a wide range from an ultraviolet range toan infrared range and including a visible range and can be a generalhalogen lamp, xenone lamp or strobo lamp. This light source 24 iscontrolled in lighting by a light source lighting apparatus 26controlled by a control part 25. A band switching filter 27 as aselecting means rotated and driven by a driving motor 28 is arranged infront of the above mentioned light source 24. This band switching filter27 is peripherally divided into three parts as shown in FIG. 3 andfilters 27a, 27b and 27c, transmitting respectively an ultraviolet band,visible band and infrared band, as shown in FIG. 5, are arrangedrespectively in the divided parts so that any of the ultraviolet band,visible band and infrared band may be selectively transmitted by thisband switching filter 27. The, above mentioned driving motor 28 iscontrolled in the rotation by a motor driver 29 controlled by thecontrol part 25.

A rotary filter 31 as a dividing means, rotated and driven by a drivingmotor 30, is arranged forward in the advancing direction of the lighthaving passed through the above mentioned band switching filter 27. Thisrotary filter 31 is peripherally divided into nine parts as shown inFIG. 4 and filters 31a to 31i transmitting respectively a red light (R),first ultraviolet light (UV1), first infrared light (IR1), green light(G), second ultraviolet light (UV2), second infrared light (IR2), bluelight (B), third ultraviolet light (UV3) and third infrared light (IR3)having respectively transmitting characteristics as are shown in FIG. 6are arranged in this order in the respective divided parts. The abovementioned first to third infrared lights are different from each otherin wavelength range and the central wavelength is longer in the order ofR1, IR2, and IR3. In the same manner, the above mentioned first to thirdultraviolet lights are different from each other in wavelength range andthe central wavelength is longer in the order of UV1, UV2 and UV3. Theabove mentioned driving motor 30 is controlled in the rotation by amotor driver 32 controlled by the control part 25.

The light emitted from the light source part 22 through the abovementioned rotary filter 31 enters the light guide 33 inserted throughthe above mentioned cable 4 and insertable part 2, is led to the tippart 9 through this light guide 33 and is emitted from a lightdistributing lens system 34 provided in this tip part 9 to illuminate anobject to be observed.

In this embodiment, the combination of the wavelength ranges of thelight emitted from the above mentioned rotary filter 31 is switched bythe band selected by the above mentioned band switching filter 27. Thatis to say, in case the infrared band is selected by the above mentionedband switching filter 27, the first to third infrared light IR1, IR2 andIR3 will be emitted in time series. In case the visible band isselected, the respective color light of red (R), green (G) and blue (B)will be emitted in time series. In case the ultraviolet band isselected, the first to third ultraviolet light UV1, UV2 and UV3 will beemitted in time series.

On the other hand, a solid state imaging device 36 as an imaging meansis arranged in the image forming position of an objective lens systemprovided in the above mentioned tip part 9. This solid state imagingdevice 36 has a sensitivity to a wide wavelength range from theultraviolet range to the infrared range and including the visible range.Also, the respective filters 31a to 31i of the above mentioned rotaryfilter 31 have transmitting characteristics within the range to whichthe above mentioned solid state imaging device 36 has a sensitivity.

The image of the observed object formed by the above mentioned solidstate imaging device 36 is photoelectrically converted and the signalscorresponding to the respective picture elements of this solid stateimaging device 36 are read out in time series as synchronized with theswitching of the illuminating light by a driver 37 controlled by thecontrol part 25. The output signal of this solid state imaging device 36is input into a video signal processing part consisting of a processcircuit 38, matrix circuit 39 and encoder 40 respectively controlled bythe control part 25. The output signals of the above mentioned solidstate imaging device 36 are first input into the process circuit 38wherein the output signals corresponding to the illuminating lights inthe respective wavelength ranges are alloted to the respective colors ofred (R), green (G) and blue (B) to produce R, G and B color signals.

The R, G and B color signals from the above mentioned process circuit 38are input into the matrix circuit 39 wherein, for example, an NTSCsystem luminance signal Y and color difference signals R-Y and B-Y areproduced by the above mentioned R, G and B signals. Further, the outputof this matrix circuit 39 is input into the encoder 40 by which an NTSCsystem video signal is produced. This video signal is input into theabove mentioned color CRT monitor and the observed object iscolor-displayed.

In this embodiment formed as in the above, the wavelength range in whichthe solid state imaging device 36 has a sensitivity is divided into ninewave-length ranges UV1 to IR3 by the rotary filter 31. Three wavelengthranges are selected from among the above mentioned nine wavelengthranges UV1 to IR3 by selecting any of the ultraviolet, visible andinfrared bands by the band switching filter 27. The combination of thesethree wavelength ranges is of the first to third ultraviolet light UV1to UV3, the respective color light of red (R), green (G) and blue (B) orthe first to third infrared light IR1 to IR3. The light of theseselected three wavelength ranges are radiated in time series onto theobserved object.

The reflected light of the observed object corresponding to therespective illuminating light of the selected three wavelength rangesare photo-electrically converted by the solid state imaging device 36,are synchronized with the switching of the illuminating light and readout in time series.

The output signals corresponding to the respective illuminating light ofthe above mentioned solid state imaging device 36 are alloted to any ofthe respective colors of red (R), green (G) and blue (B) and areprocessed to be video signals in the video signal processing part 41.

The observed object is color-displayed by the respective alloted colors.That is to say, in case the ultraviolet band or infrared band isselected by the band switching filter 27, the observed object will bedisplayed in quasi colors.

Thus, according to this embodiment, the observed object can becolor-displayed by selecting any of the ultraviolet, visible andinfrared bands and alloting them to any colors. Therefore, the colortone differences in the respective positions of the observed objectdifficult to discriminate in a picture image in a general visible rangecan be easily detected.

The band switching filter 27 is not limited to be divided into theultraviolet range, visible range and infrared range but, for example, afilter in which the long wavelength side of the visible range and a partof the short wavelength side of the infrared range are made transmittingbands may be provided so that the light having passed through thisfilter may be transmitted through the rotary filter 31, the respectivecolor light of green (G) and red (R) and the first infrared light (IR1)may be radiated in time series onto the observed object and therespective colors of blue (B), green (G) and red (R) may be alloted tothe above mentioned respective color light of green(G) and red(R) andthe first infrared light(IR1) so as to be color-displayed. These colorpicture image may be compared with a color picture image in a generalvisible range. Thus, various color picture images can be obtained by thecombination of the band switching filters 27 and rotary filter 31.

The above mentioned band switching filter 27 and rotary filter 31 may bearranged between the light source 24 and solid state imaging device 36and the arranging order can be freely determined.

The arrangement in time series of the respective filters 31a to 31i ofthe rotary filter 31 can be properly set in relation to the timing ofreading out of the solid state imaging device 36.

The light source 24 is not limited to emit the light of all theultraviolet, visible and infrared ranges but, for example, a pluralityof light sources each emitting the light of at least one band may beprovided to be used as switched.

For example, in case a line transfer type CCD is used for the solidstate imaging device 36, for example, in case the respective color lightof red(R), green(G) and blue(B) are used for the illuminating light,UV1+IR1, UV2+IR2 and UV3+IR3 may be used for the light interceptingparts and, in case IR1 to IR3 are used for the illuminating light,G+UV2, B+UV3 and R+UV1 may be used for the light intercepting parts.

A strobo lamp which can be switched on and off at a high speed may beused instead of using a wavelength band limiting filter as the bandswitching filter 27 so that light may be emitted when the filters of thewavelength bands UV1 to UV3, B, G and R and IR1 to IR3 which arerequired among the respective filters 31 are in the light path and theother filter parts may be used for the read out periods.

The second embodiment of the present invention is shown in FIGS. 7 and8.

In this embodiment, a plurality of light sources respectively emittinglight of different specific wavelength ranges are provided. Such narrowband light sources as lasers are used for this plurality of lightsources 45a to 45d. One to three light sources are selected by thecontrol part 25 from among the above mentioned plurality of lightsources 45a to 45d and are made to emit lights in time series assynchronized with the timing of reading out of the solid state imagingdevice 36. The light of the selected three wavelength ranges areradiated in time series onto the observed object. The other formationsare the same as in the first embodiment.

There is a means by which the light emitted selectively from the abovementioned plurality of light sources 45a to 45d are made to enter onelight guide 33 as is shown, for example, in FIG. 7. That is to say, onelight source 45a is arranged in the position in which the light emittedfrom this light source 45a directly enters the light guide 33 and thelight emitted from the other light sources 45b to 45d are made to enterthe above mentioned light guide 33 respectively through mirrors 46b to46d and through rotatable mirrors 47b to 47d arranged between the abovementioned light source 45a and light guide 33. In case the light emittedfrom the light source 45a is to be made to enter the light guide 33, allthe above mentioned mirrors 47b to 47d are retreated from theilluminating light path of the light source 45a. In case the lightemitted from the other light sources 45b to 45d are to be made to enterthe light guide 33, only the mirror corresponding to the light sourcemade to emit the light among the above mentioned mirrors 47b to 47d isinterposed in the illuminating light path of the light source 45a.

As another means by which the lights emitted selectively from the abovementioned plurality of light sources 45a to 45b are made to enter onelight guide 33, for example, as shown in FIG. 8, the plurality of lightsources 45a to 45d may be made integrally movable and the light sourceto emit the light may be selectively opposed to the entrance end of thelight guide 33.

For the lamps to be used for the light sources 45a to 45d shown in FIGS.7 or 8, there are enumerated a laser and LED each emitting a light bylimiting the wavelength. A xenone lamp, halogen lamp and strobo lamp ineach of which an absorption type filter or evaporative deposition typefilter in which a color is mixed may be provided in the emitting portemitting a light in a wide band may be provided to limit the outputwavelength.

According to this embodiment, the wavelength range can be selected morefreely.

The third embodiment of the present invention is shown in FIGS. 9 to 11.

In this embodiment, a color filter 50 as is shown in FIG. 10 is arrangedin front of the light source 24. This color filter 50 is divided intonine parts in the peripheral direction the same as in the rotary filter31 in the first embodiment. Filters 50a to 50i transmitting a redlight(R), first ultraviolet light(UV1), first infrared light(IR1), greenlight(G), second ultraviolet light(UV2), second infrared light(IR2),blue light(B), third ultraviolet light(UV3) and third infraredlight(IR3) respectively having transmitting characteristics as are shownin FIG. 6 are arranged in this order in the divided respective parts.Light intercepting parts 51 are provided respectively between the abovementioned filters 50a to 50i.

The light of the respective wavelength ranges having passed through theabove mentioned respective filters 50a to 50i are radiated in timeseries onto an object to be observed.

In case the wavelength range of this illuminating light is switched, alight intercepting period corresponding to the above mentioned lightintercepting part 51 will be provided. In this embodiment, the signal ofthe solid state imaging device 36 is read out in this light interceptingperiod.

Also, in this embodiment, a selecting circuit 52 is provided between theabove mentioned solid state imaging device 36 and video signalprocessing part 41 and is controlled by the control part 25 so that theoutput signal of the above mentioned solid state imaging device 36 maybe selected and delivered to the video signal processing part 41.

The timing of the selection of this selecting circuit 52 is shown inFIGS. 11(A) to 11(E). That is to say, when the observation is in thevisible band, the signal will be selected at the time of reading outcorresponding to the illuminating light of R, G and B as shown in FIG.11(B) for the timing of the illuminating light shown in FIG. 11(A). Inthe case when the observation is in the ultraviolet band, the signalwill be selected at the time of reading out corresponding to theilluminating light of UV1, UV2 and UV3 as shown in FIG. 11(C). When theobservation is in the infrared band, the signal will be selected at thetime of reading out corresponding to the illuminating light of IR1, IR2and IR3 as shown in FIG. 11(D). When the observation is in the band of apart of the long wavelength side of the visible range and the shortwavelength side of the infrared range, the signal will be selected atthe time of reading out corresponding to the illuminating light of R,IR1 and G.

According to this embodiment, the wavelength range can be selected morefreely the same as in the second embodiment.

In the above mentioned first to third embodiments, the illuminatinglight may be radiated onto the observed object and the light havingpassed through this observed object may be received. The imaging meansis not limited to the solid state imaging device provided in the tippart of the endoscope but may be a television camera externally fittedto the eyepiece part of the endoscope transmitting the observed imagethrough the image guide.

The fourth embodiment of the present invention is shown in FIGS. 12 to15.

In this embodiment, the observing wavelength band can be switched byusing a strobo lamp 24S for the light source 24 instead of the bandswitching filter 27, motor 28 and motor driver 29 in the firstembodiment. Also, in this embodiment, a rotary filter 55 different inthe arrangement from the rotary filter 31 in the first embodiment isprovided instead of the rotary filter 31 and is divided into nine partsin the peripheral direction as shown in FIG. 13. Filters 55a to 55itransmitting respectively R, G, B, IR1, IR2, IR3, UV1, UV2 and UV3 arearranged in this order in the divided respective parts. Lightintercepting parts 56 are provided respectively between the filters 55ato 55i.

When the above mentioned rotary filter 55 is rotated, as shown in FIG.14(A), the respective filters 55a to 55i of the above mentioned rotaryfilter 55 will be interposed in time series in the illuminating lightpath of the above mentioned strobe lamp 24S. The above mentioned strobolamp 24S which can emit a light within a short time will emit a lightwhen the filter corresponding to the wavelength range selected by thecontrol part 25 comes into the light path. The object imagecorresponding to the light emitted from this strobo lamp 24S and havingpassed through the selected filter will be imaged by the solid stateimaging device 36.

The other formations are the same as in the first embodiment.

In this embodiment, as shown, for example, in FIG. 14(B), the strobolamp 24S will emit the light when the filters 55a, 55b and 55ccorresponding respectively to the wavelength ranges of R, G and B comeinto the light path. A color picture image in the ordinary visible rangewill be obtained when the respective colors of R, G and B are alloted tothe above mentioned wavelength ranges of R, G and B.

Also, as shown in FIG. 14(C), when the filters 55d, 55e and 55fcorresponding respectively to the wavelength ranges of IR1, IR2 and IR3come into the light path, the strobo lamp 24S will emit a light and theobject image in the infrared range will be displayed in quasi colors. Inthe same manner, as shown in FIG. 14(D), when the filters 55g, 55h and55i corresponding respectively to the wavelength ranges of UV1, UV2 andUV3 come into the light path, the strobo lamp 24S will emit a light andthe object image in the ultraviolet range will be displayed in quasicolors.

Now, the spectral characteristic variation of blood in which Indocyaninegreen(ICG) which is an infrared ray absorbing color is mixed is shown inFIG. 15. As shown in this diagram, the blood in which ICG is mixed has amaximum absorption of 805 nm. Therefore, the filter 55e corresponding toIR2 is made to have a band pass characteristic of an absorption factorhaving a maximum of 805 nm./in the center and the filter 55fcorresponding to IR3 is made to be of a characteristic of transmitting awavelength range of more than 850 nm. wherein the variation of theabsorption factor is little recognized. The above mentioned ICD is mixedin blood, for example, by a venous injection. The strobo lamp 245 willemit a light when the filter 55e, 55f and 55b corresponding respectivelyto the wavelength ranges of IR2, IR3 and G as shown in FIG. 14(e) comeinto the light path. When the imaged object is displayed in quasi colorsby the combination of the wavelength ranges of the above mentioned IR2,IR3 and G, the running state of the veins below the mucous membrane willbe able to be confirmed by the difference between the outputs of IR2 andIR3. That is to say, when the infrared light high in the transmittivitythrough the tissue is used, the light will be able to reach the deeppart of the tissue. On the other hand, as the blood has a maximumabsorption at 805 nm. by the action of the above mentioned ICG, IR2 ofIR2 and IR3 of the same reaching degree in the tissue will be moreabsorbed and will become a shadow in the vein part in the picture imageby IR2. Therefore, by taking the difference from the picture image byIR3, the running state of the blood can be video-imaged at a highcontrast. Also, by the picture image by G, the concavo-convexes andcongested state on the surface of the mucous membrane can be definitelyconfirmed and the diagnosing activity can be improved.

Also, as shown in FIG. 14(F), when the filter corresponding to thespecific single wavelength range comes into the filter light path, thestrobo lamp 24S will emit a light and the object image in thiswavelength range may be monocolor-displayed. In FIG. 14(F), only thepicture image by B is obtained. However, the absorption in the shortwavelength of B of the short wavelength is higher than the absorptioncharacteristic of hemoglobin by R, IR1, IR2 and IR3 on the longwavelength side and therefore the distribution of the hemoglobin on thesurface of the mucous membrane can be definitely observed. Also, byusing another single wavelength range, a disease or the like can bediagnosed from the difference in picturing between the wavelengthranges.

Further, by forming the rotary filter 55 in a filter arrangement as isshown in FIG. 13, when the ordinary color displaying by R, G and B, asthe filters 55a, 55b and 55c corresponding to the wavelength ranges ofR, G and B are adjacent, there is an effect that the color displacementcan be reduced.

The fifth embodiment of the present invention is shown in FIGS. 16 to18.

This embodiment is an endoscope apparatus in which a television camerais externally fitted to the eyepiece part of a fiberscope.

As shown in FIG. 16, a fiberscope 60 is provided with an elongated, forexample, flexible insertable part 62 and a large diameter operating part63 is connected to the rear end of this insertable part 62. A flexiblelight guide cable 64 is extended sidewise from the rear end part of theabove mentioned operating part 63. An eyepiece part 65 is provided atthe rear end of the above mentioned operating part 63.

A light guide 69 is inserted through the above mentioned insertable part62 and is arranged on tip surface in the tip part 66 of the insertablepart 62 so that an illuminating light may be emitted from this tip part66. The above mentioned light guide 69 is inserted on the entrance endside through the above mentioned light guide cable 64, is connected to aconnector not illustrated provided in the tip part of this light guidecable 64 and is connected to the control apparatus 6 through thisconnector so that the light emitted from the strobo lamp 24S within thecontrol apparatus 6 may be incident.

The above mentioned tip part 66 is provided with an objective lenssystem 67. The tip surface of the image guide 68 is arranged in theimage forming position of this objective lens system 67. This imageguide 68 is inserted through the above mentioned insertable part 62 andis extended to the above mentioned eyepiece part 65. An object imageformed by the above mentioned objective lens system is led to theeyepiece part 65 by the above mentioned image guide 68 so as to beobserved from this eyepiece part 65.

An externally fitted television camera 70 is removably fitted to theabove mentioned eyepiece part 65. This externally fitted televisioncamera 70 is provided with an image forming lens 71 forming an image ofthe light from the above mentioned eyepiece part 65 and a solid stateimaging device 72 arranged in the image forming position of this imageforming lens 71. This solid state imaging device 72 is driven by thedriver 37 within the control apparatus 6 the same as in the fourthembodiment and the signal read out is processed by the signal processingpart 41.

The other formations are substantially the same as in the fourthembodiment but a rotary filter 58 is provided instead of the rotaryfilter 55 in the fourth embodiment. As shown in FIG. 17, this rotaryfilter 58 is divided into ten parts in the peripheral direction. Filters58a to 58j respectively transmitting R, G, B, IR1, IR2, IR3, UV1, UV2,UV3 and W (white light) are arranged in this order in the dividedrespective parts. The filter 58j transmitting W is provided to enablethe observation by a general visible light from the eyepiece part 65 ofthe fiberscope 60 and may be a filter transmitting substantially all thelight emitted from the above mentioned strobo lamp 24 or may be a filtertransmitting only a visible light range. Light intercepting parts 59 areprovided respectively between the filters 58a to 58j.

When the above mentioned rotary filter 58 is rotated, as shown in FIG.18(A), the respective filters 58a to 58j of the above mentioned rotaryfilter 58 will be interposed in time series in the illuminating lightpath of the above mentioned strobo lamp 24S. The above mentioned strobolamp 24S will emit a light when the filter corresponding to thewavelength range selected by the control part 25 comes into the lightpath. The light emitted from this strobo lamp 24S and transmittedthrough the selected filter enters the entrance end of the light guide69 and is emitted from the tip part 66. The returning light from theobject by this illuminating light is formed to be an image on the tipsurface of the image guide 68 by the objective lens system 67. Thisobjective image is led to the eyepiece part 65 by the image guide 68 andis further imaged by the solid state imaging device 72 within theexternally fitted television camera 70 connected to this eyepiece part65.

In this embodiment, the same as in the fourth embodiment, as shown inFIG. 18(B), when the filters 58a, 58b and 58c corresponding respectivelyto the wave-length ranges of R, G and B come into the light path, thestrobo lamp 24S will emit a light and, by alloting the respective colorsof R, G and B to the wavelength ranges of the above mentioned R, G andB, a color image in the ordinary visible range will be obtained.

Also, as shown in FIG. 18(C), when the filters 58d, 58e and 58fcorresponding respectively to the wave-length ranges of IR1, IR2 and IR3come into the light path, the strobo lamp 24S will emit a light and theobject image in the infrared range will be displayed in quasi colors. Inthe same manner, as shown in FIG. 18(D), when the filters 58g, 58h and58j corresponding respectively to the wavelength ranges of UV1, UV2 andUV3 come into the light path, the strobo lamp 24S will emit a light andthe object image will be displayed in quasi colors.

The same as in the fourth embodiment, the filter 58e corresponding toIR2 is made to be of a band pass characteristic of having 805 nm. in thecenter and the filter 58f is made to be of a characteristic oftransmitting a wavelength range of more than 850 nm. The above mentionedICG is mixed in blood. When the filters 58e, 58f and 58b correspondingrespectively to the wavelength ranges of IR2, IR3 and G come into thelight path, the strobo lamp 24S will emit a light. When the object isdisplayed in quasi colors by the combination of the wavelength ranges ofthe above mentioned IR2, IR3 and G, the running state of the veins belowthe mucous membrance will be able to be confirmed by the differencebetween the outputs of IR2 and IR3. Also, by the picture image by G, theconcavo-convexes and congested state on the surface of the mucousmembrane can be definitely confirmed and the diagnosing activity can beimproved.

As shown in FIG. 18(F), when a filter corresponding to a specific singlewavelength range comes into the light path, the strobo lamp 24S willemit a light and the object image of this wavelength range will bemonocolor-displayed.

When the above mentioned rotary filter 58 is stopped in the position inwhich the filter 58j transmitting W is interposed in the light path, thelight of the visible light range will be constantly emitted andtherefore the naked eye observation will be able to be made from theeyepiece part 65 of the fiberscope 60.

Thus, according to this embodiment, even if not only such electronicendoscope 1 as is shown in the first to fourth embodiments but also thegenerally used fiberscope 60 is used, the observation will be possibleby selecting any wavelength range in wavelength ranges including othersthan the visible light range.

The other operations and effects are the same as in the fourthembodiment.

The sixth embodiment of the present invention is shown in FIGS. 19 to21.

In this embodiment, a reflecting mirror is used as a selecting meansinstead of the band switching filter 27 in the first embodiment.

As shown in FIG. 19, a band switching apparatus 80 is provided withinthe light source part 22. As shown in FIG. 20, this band switchingapparatus 80 is provided with a band switching mirror 81 having threemirrors 81a, 81b and 81c arranged in a row and respectively different inreflective characteristic. This band switching mirror 81 is arranged toreflect at a predetermined angle the emitted light from the abovementioned light source 24 and is movable in the arranging direction (thedirection indicated by the arrows in the drawing) of the mirrors 81a,81b and 81c along a rail (not illustrated) so that the light emittedfrom the above mentioned light source 24 may be reflected selectively byany of the mirrors 81a, 81b and 81c.

The reflective characteristics of the above mentioned mirrors 81a, 81band 81c are as shown, for example, in FIG. 21.

That is to say, the mirror 81a reflects only substantially theultraviolet light range, the mirror 81b reflects only substantially thevisible light range and the mirror 81c reflects only substantially theinfrared light range.

Also, as shown in FIG. 20, a rack 82 is provided in the moving directionon a frame 81d of the above mentioned band switching mirror 81. A piniongear 84 rotated by a motor 83 is meshed with this rack 82. The abovementioned motor 83 is rotated by a motor driver 86 controlled by a bandswitching controlling part 85. The above mentioned band switching mirror81 is moved by rotating the above mentioned pinion gear 84. Three kindsof aperture windows 87a, 87b and 87c of apertures of respectivelydifferent areas are provided at intervals equal to those of the abovementioned mirrors 81a, 81b and 81c in the moving direction. A lightemitting device 88 and light receiving sensor 89 are provided in thepositions holding the above mentioned band switching mirror 81 andopposed selectively to the above mentioned aperture windows 87a, 87b and87c so that the output of this light receiving sensor 89 may be inputinto the above mentioned band switching controlling part 85. The abovementioned aperture window 87 a is provided in the position opposed tothe light emitting device 88 and light receiving sensor 89 when themirror 81a is interposed in the illuminating light path. The aperture87b is provided in the position opposed to the light emitting device 88and light receiving sensor 89 when the mirror 81b is interposed in theilluminating light path. The aperture window 87c is provided in theposition opposed to the light emitting device 88 and light receivingsensor 89 when the mirror 81c is interposed in the illuminating lightpath. In the above mentioned band controlling part 85, which of themirrors 81a, 81b and 81c is interposed in the illuminating light pathcan be discriminated by the difference in the amount of light receivedby the above mentioned light receiving sensor 89.

The light reflected by any of the above mentioned mirrors 81a, 81b and81c is reflected by a mirror 90 reflecting the light of all theultraviolet to infrared band. The light reflected by the mirror 90enters the rotary filter.

The other formations are the same as in the first embodiment.

In this embodiment, when any of the ultraviolet visible and infraredobserving bands is selected in the band switching controlling part 85,the motor 83 will be rotated through the motor driver 86 and the bandswitching mirror 81 will be moved in the directions indicated by thearrows in the drawing. When any of the mirrors 81a, 81b and 81ccorresponding to the selected band is interposed in the illuminatinglight path, any of the aperture window 87a, 87b and 87c corresponding tothis mirror will be positioned between the light emitting device 88 andlight receiving sensor 89 and the light emitted from the light emittingdevice 88 will be received by the light receiving sensor 89 through theabove mentioned aperture window. In case the light amount received bythis light receiving sensor 89 coincides with the light amount set inadvance by the area of the aperture window corresponding to the selectedband, the rotation of the above mentioned motor 83 will be stopped andthe band switching mirror 81 will be stopped. Thus, the mirrorreflecting only the light of the selected band will be interposed in theilluminating light path. The lights reflected by the mirrors 81a, 81band 81c are reflected by the mirror 90 and enter the entrance end of thelight guide 33.

For example, when the visible band is selected, as shown in FIG. 19, themirror 81b, reflecting only the visible light, will be interposed in theilluminating light path and the light emitted from the light source 24will be reflected by the mirror 81b to be a visible light and will befurther transmitted through the rotary filter 31 to be divided in timeseries into light of the respective wavelength bands of R, G and B. Whenthe ultraviolet band is selected, the mirror 81a reflecting only theultraviolet light will be interposed in the illuminating light path andthe light emitted from the light source 24 will be reflected by themirror 81a to be an infrared light and will be further transmittedthrough the rotary filter 31 to be divided in time series into light ofthe respective wavelength bands of UV1, UV2 and UV3. In case theinfrared band is selected, the mirror 81c reflecting only the infraredlight will be interposed in the illuminating light path and the lightemitted from the light source 24 will be reflected by the mirror 81c tobe an infrared light and will be further transmitted through the rotaryfilter 31 to be divided in time series into light of the respectivewavelength bands of IR1, IR2 and IR3.

The other operations and effects are the same as in the firstembodiment.

The above mentioned mirrors 81a, 81b and 81c are not limited to bedivided into the ultraviolet, visible and infrared ranges but may haveany spectral characteristics.

A modification of the sixth embodiment is shown in FIGS. 22 and 23.

In this modification, a rotary mirror 91 in which the observing band isswitchable by rotation is provided instead of the band switching mirror81 in the sixth embodiment.

In the above mentioned rotary mirror 91, as shown in FIG. 23, adisc-like frame 91d is divided into three parts in the peripheraldirection and a mirror 91a reflecting only the ultraviolet light, mirror91b reflecting only the visible light and mirror 91c reflecting only theinfrared light are provided in the divided respective parts. This rotarymirror 91 is rotated and driven by a motor 92. This motor 92 is rotatedby a motor driver 93 controlled by the band switching controlling part85. As shown in FIG. 23, in the above mentioned rotary mirror 91, threekinds of aperture windows 94a, 94b and 94c of apertures of respectivelydifferent areas are provided in the rotating direction in response tothe above mentioned mirrors 91a, 91b and 91c. The same as in the sixthembodiment, the above mentioned aperture windows 94a, 94b and 94c are tobe selectively positioned between the light emitting device 88 and lightreceiving sensor 89 arranged to hold the above mentioned rotary mirror91. Which of the mirrors 91a, 91b and 91c is interposed in theilluminating light path can be discriminated by the amount of lightreceived by the above mentioned light receiving sensor 89.

The other formations, operations and effects are the same as in thesixth embodiment.

The seventh embodiment of the present invention is shown in FIGS. 24 and25.

In this embodiment, a rotary mirror 95 is provided instead of the rotaryfilter in the sixth embodiment.

In the above mentioned rotary mirror 95, as shown in FIG. 25, adisc-like frame is divided into nine parts in the peripheral directionand mirrors 95a to 95i reflecting respectively only R, G, B, IR1, IR2,IR3, UV1, UV2 and UV3 are arranged in this order in the dividedrespective parts. Light intercepting parts 96 reflecting no light of anyband are provided between the respective mirrors 95a to 95i. The abovementioned rotary mirror 95 is rotated and driven by a motor 97 which isrotated by a motor driver 98 controlled by the control part 25.

The above mentioned rotary mirror 95 is so arranged that the lightreflected by the band switching mirror 81 may be reflected by any of themirrors 95a to 95i and this reflected light may enter the entrance endof the light guide 33.

The other formations are the same as in the sixth embodiment.

In this embodiment, any of the observing bands of the ultraviolet,visible and infrared light is selected by the band switching mirror 81and is divided in time series into light of respective wavelength bandsof R, G and B.

The other operations and effects are the same as in the sixthembodiment.

In this embodiment, the rotary mirror 91 in the modification of thesixth embodiment may be used instead of the band switching mirror 81 orthe band switching filter 27 in the first embodiment may be used.

The eighth embodiment of the present invention is shown in FIGS. 26 to29.

As shown in FIG. 26, a light guide 114 transmitting an illuminatinglight in inserted through the insertable part of the electronicendoscope 1. The tip surface of this light guide 114 is arranged in thetip part 9 of the insertable part 2 so that the illuminating light canbe emitted from this tip part 9. The above mentioned light guide 114 isinserted on the entrance end side throughout the universal cord 4 and isconnected to the connector 5. An objective lens system 115 is providedin the above mentioned tip part 9. A solid state imaging device 116 isarranged in the image forming position of this objective lens system 115and has a sensitivity to a wide wavelength range from the ultravioletrange to the infrared range and including the visible range. A liquidcrystal shutter 117 temporarily intercepting the light entering thissolid state imaging device 116 is provided on the front surface of thissolid state imaging device 116. Signal lines 126 and 127 are connectedto the above mentioned solid state imaging device. A signal line 128 isconnected to the above mentioned liquid crystal shutter 117. Thesesignal lines 126, 127 and 128 are inserted through the above mentionedinsertable part 2 and universal cord 4 and are connected to the abovementioned connector 5.

On the other hand, a lamp 121 emitting a light in a wide range from theultraviolet light to the infrared light is provided within the controlapparatus 6 A general xenone lamp or strobo lamp can be used for thislamp 121. The above mentined xenone lamp or strobo lamp emits a largeamount of not only a visible light but also ultraviloet and infraredlights. This lamp 121 is fed with an electric power by a current sourcepart 122. A rotary filter 124 as a dividing means rotated and driven bya motor 123 is arranged in front of the above mentioned lamp 121. asshown in FIG. 27, this rotary filter 124 is divided into eight parts inthe peripheral direction. As shown in FIG. 28, filters 124a to 124htransmitting respectrively the red light (R), green light (G), bluelight (B), first ultraviolet light (UV1), second ultraviolet light(UV2), first infrared light (IR1), second infrared light (IR2) and thirdinfrared light (IR3) and having a band pass characteristic ofselectively transmitting the wavelength of a narrow band overultraviolet light to infrared light bands are arranged in this order inthe divided respective parts. The above mentioned first to thirdinfrared light are different from each other in the wavelength range andthe wavelength is longer in the order of IR1, IR2 and IR3. In the samemanner, the above mentioned first and second ultraviolet light aredifferent from each other in the wavelength range and the wavelength islonger in the order of UV1 and UV2. The above mentioned motor 123 iscontrolled to be rotated and driven by a motor driver 125.

The light having passed through the above mentioned rotary filter 124enters the entrance end of the above mentioned light guide 114, is ledto the tip part 9 through this light guide 114 and is emitted out ofthis tip part 9 to illuminate the observed position.

The returning light from the observed position by this illuminatinglight is made to form an image on the solid state imageing device 116 bythe objective lens system 115 and is photoelectrically converted. Adriving pulse from a driver circuit 131 within the above mentionedcontrol apparatus 6 is applied to this solid state imaging element 116through the above mentioned signal line 126. The reading out andtransfer are made by this driving pulse. The video signal read out ofthis solid state imaging device 116 is input into a pre-amplifier 132provided within the above mentioned control apparatus 6 or electronicendoscope 1 through the above mentioned signal line 127. The videosignal amplified by this pre-amplfier 132 is input into a processingcircuit 133, is processed to be γ-corrected and white-balanced and isconverted to a digital signal by an A/D converter 134. This digitalvideo signal is to selectively stored in three memories (1)136a, (2)136band (3)136c corresponding to the respective colors, for example, of red(R), green (G) and blue (B) by a selecting circuit 135. The signals ofthe above mentioned memories (1)136a, (2)136b and (3)136c aresimultaneously read out, are converted to analogue signals by a D/Aconverter 137, are output as R, G and B color signals, are input into anencoder 138 and are output out of this encoder 138 as an NTSC compositesignal.

The above mentioned R, G and B color signals or NTSC composite signal isinput into the color monitor 7 and the observed position iscolor-displayed by this color monitor 7.

The above mentioned liquid crystal shutter 117 is connected to a shutterdriver 141 within the above mentioned control apparatus 6 through thesignal line 128 and is opened and closed by this shutter driver 141.

A timing generator 142 making a timing of the entire system is providedwithin the above mentioned control apparatus 6 so that such respectivecircuits as the motor drive 25 and driver circuit 131 may besynchronized.

Within the above mentioned control apparatus 6, there is provided aswitching circuit 143 controlling the shutter driver 141 so that, assynchronized with the above mentioned timing generator, the light mayenter the solid state imaging device 116 only at the time of theillumination by the filter of any transmitted wavelength range of theoperator in the above mentioned rotary filter 124. Also, this switchingcircuit 143 controls the above mentioned selecting circuit 135 so thatthe video signals corresponding to the respective wavelength rangesselected by the liquid crystal shutter 117 driven by the abovementioned. shutter driver 141 may be stored in the respectivelydifferent memories 136a to 136c. Further, the above mentioned switchingcircuit 143 controls the current source part 122 so that, when the abovementioned liquid crystal shutter 117 is closed and the solid stateimaging device 116 receives no light, the emitted light amount of thelamp 121 will be reduced.

The operation of this embodiment formed as in the above shall beexplained in the following.

When the lamp 121 emits a light and the rotary filter 124 is rotated bythe motor 123 in the light path of the light of this lamp 121, the lightof the wavelength range in the wide band from the ultra-violet light tothe infrared light as emitted from the above mentioned lamp 121 will betransmitted in turn through the respective filters 124a to 124h of theabove mentioned rotary filter 124 and will be separated in time seriesinto color light of the wavelength range shown in FIG. 28. This light isradiated onto an observed object out of the tip part 9 of the insertablepart 2 of the electronic endoscope 1 inserted in a body cavity throughthe light guide 114. The returning light from the observed object bythis illuminating light is made to form an image on the solid stateimaging device 116 by the object lens system 115.

Here, if, for example, any three wavelength ranges are selected fromamong the divided wavelength ranges as shown in FIG. 28, when thefilters corresponding to the selected wavelength ranges from among therespective filters 124a to 124h of the above mentioned rotary filter areinserted in the illuminating light path, by the drive of the shutterdriver 141, the liquid crystal shutter 117 will open, the abovementioned solid state imaging device 116 will be exposed and a videosignal will be obtained. On the other hand, when the filterscorresponding to the wavelength ranges not selected are inserted in theilluminating light path, the above mentioned liquid crystal shutter 117will close and the above mentioned solid state imaging device 116 willnot be exposed. Thus, only the video images of the object illuminated bythe light transmitted through the filters corresponding to thewavelength ranges selected by the switching circuit 143 among therespective filters 124a to 124h of the rotary filter 124 will be readout in time series by the driver circuit 131 synchronized with thetiming generator 142. The signals read out of this solid state imagingdevice 116 are amplified by the pre-amplifier 132, are processed to beγ-corrected and white-balanced by the processing circuit 133 and arethen converted to digital signls by the A/D converter 134 and the videosignals read out in time series by the selecting circuit 135 are storedrespectively in the memories (1)136a, (2)136b and (3)136c correspondingto the respective colors of R, G and B for the respective wavelengthranges. The signals simultaneously read out of the memories 136a, 136band 136c are converted to analogue signals by the D/A converter 137 andare output as R, G and B signals in the color monitor 7 capable ofinputting R, G and B signals. Respective colors of R, G and B arealloted to the selected wavelength ranges and the observed object isdisplayed in quasi colors. Also, the above mentioned R, G and B signalsare converted to an NTSC composite signal by the encoder 138, thissignal is input into the color monitor and the observed object isdisplayed in quasi colors in the same manner. When respectivetransmitted wavelength ranges of R, G and B are selected and therespective colors of R, G and B are alloted to the respectivetransmitted wavelength ranges or R, G and B, an ordinary color pictureimage will be obtained.

As synchronized with the above mentioned timing generator 142, the abovementioned switching circuit 143 will reduced the emitted light amount ofthe lamp 121 when the liquid crystal shutter 117 is closed but willincrease the emitted light amount of the lamp 121 when the liquidshutter 117 is opened.

Thus, according to this embodiment, any wavelength ranges can beselected from among the wavelength ranges divided as shown in FIG. 28 inthe ranges of not only the visible range but also from the ultravioletlight range to the infrared light range, the observed object can becolor-displayed with any color allotment and an optimum observingwavelength band can be selected in response to the observed object.

Therefore, the color tone difference in the respective positions of theobserved object difficult to discriminate in a picture image in ageneral visible range can be easily detected and a disease can be easilydetected.

For example, as shown in FIG. 29, by selecting a wavelength rangeincluding absorption peaks different with the respective colors of aliving body or a wavelength range in which the difference of theabsorption factor with other colors is the largest, the colordistribution in the living body tissue can be detected.

Further, by using a light of a long wavelength range above 600 nm. highin the transmittivity in a living body, the veins running below themucous membrane and the pentration range of a disease can be easilyobserved. Thus, according to this embodiment, there is an effect thatthe diagnosing activity can be improved.

The solid state imaging device 116 may be a device provided with lightintercepting parts to be transferred or a device provided with no lightintercepting part.

The position of the liquid crystal shutter 117 is not limited to be infront of the solid state imaging device 116 but may be between the lamp121 and solid state imaging device 116. For example, the liquid crystalshutter 117 may be provided in front of the lamp 121 as shown in FIG.30, at the entrance end of the light guide 114 as shown in FIG. 31 or atthe exit end of the light guide 114.

The ninth embodiment of the present invention is shown in FIGS. 33 and34.

In this embodiment, the solid state imaging device 116 in the eighthembodiment is made an interline type CCD 150 and a shutter 160 using apiezoelectric device is provided instead of the liquid crystal shutter160.

As shown in FIG. 33, the above mentioned CCD 150 has each pictureelement 154 formed of a photosensitive part 151 receiving a light andphotoelectrically converting it to an electric signal, a read-out gate152 reading out a signal charge accumulated in this photosensitive partand a vertically transferring CCD 153 transferring in the verticaldirection the signal charge read out of this readout gate 152 and isfurther provided with a horizontally transferring CCD 155 transferringin the horizontal direction the charge transferred by the abovementioned vertically transferring CCd 153. The rate occupied by theabove mentioned light receiving part 151 in the entire CCd 150 is lessthan 50% as there are the read-out gate 152 and vertically transferringCCD 153.

On the other hand, the above mentioned shutter 160 is arranged in frontof the above mentioned CCD 150 and, as shown in FIG. 34(A), is formed ofa filter 163 in which the width of each picture element 154 of the abovementioned CCd 150 is divided into two parts, a transmitting part 161 isarranged on one part and a light intercepting part 162 is arranged onthe other part and piezoelectric devices 164a and 164b fitted to bothend parts in the arranging direction of the transmitting part 161 andlight intercepting part 162 of this filter 163. The above mentionedpiezoelectric devices 164a and 164b are driven by a shutter driver 141and , when one contracts, the other will extend so that the abovementioned filter 163 may be parallelly moved in the horizontal directionby half the picture element part. The transmitting part 161 can beswitched to be positioned on the photosensitive part 151 of the CCD 150as shown in FIG. 34(B) and the light intercepting part 162 can beswitched to be positioned on the above mentioned photosensitive part151.

The other formations are the same as in the eighth embodiment.

In this embodiment, the same as in the eighth embodiment, the lightemitted from the lamp 121 is color-separated in time series by therotary filter 124 and is radiated onto the observed position through thelight guide 114. The returning light from this observed position is madeto form an image on the above mentioned CCD 150 by the objective linessystem 115.

Here, if any wavelength ranges are selected from among the wavelengthranges divided as shown in FIG. 28 by the switching circuit 143, whenthe filters corresponding to the selected wavelength ranges among therespective filters 124a to 124h of the above mentioned rotary filter 124are inserted in the illuminating light path, the piezoelectric devices164a and 164b will be driven and, as shown in FIGS. 34(A), thetransmitting part 161 will be positioned on the photosensitive part 151to make exposure. On the other hand, when the filters corresponding tothe wavelength ranges not selected are inserted in the illuminatinglight path, as shown in FIG. 34(B), the light intercepting part 162 willbe positioned on the above mentioned photosensitive part 151 to make noexposure.

Thus, according to this embodiment, the same as in the eighthembodiment, only the video images of the object illuminated by the lighttransmited through the filters corresponding to the wavelength rangesselected by the switching circuit 143 among the respective filters 124ato 124h of the rotary filter 124 will be read out in time series.

Also, in this embodiment, the transmitting part 161 and lightintercepting part 162 of the above mentioned shutter 160 can be arrangedin any proportion on the photosensitive part 151 of the CCD 150 withoutbeing perfectly switched over to each other. Thereby, the shutter 160can be made to have the same function as a diaphragm. Therefore, whenthe reflection factors of the mucous membrane tissue in the respectivewavelength ranges are extremely different, the video image by therespective wavelenght ranges can be made proper.

The other operations and effects are the same as in the eighthembodiment.

The tenth embodiment of the present invention is shown in FIGS. 35 to38.

in this embodiment, a CCD 170 fitted with an electronic shutte is usedinstead of the solid state imaging device 116, liquid crystal shutter117 and shutter driver 141 in the eighth embodiment.

As shown in FIG. 36, the above mentioned CCD 170 fitted with anelectronic shutter is provided with an imaging part 173 formed of alight receiving part photoelectrically converting an optical pictureimage to a video signal and a vertically reading-out register 172reading out the electric charge of this light receiving part, anaccumulating part 174 accumulating the video signals of the respectivelines of the above mentioned vertically reading-out register 172, ahorizontally reading-out register 175 horizontally reading out as avideo signal the electric charge accumulated in the above mentionedaccumulating part 174 and a charge absorbing drain 176 absorbind theunnecessary charge read out by the above mentioned verticallyreading-out register 172.

The above mentioned CCD 170 fitted with an electronic shutter is drivenby a driver circuit 178.

In this embodiment, the same as in the eighth embodiment, the lightemitted from the lamp 121 is color-separated in time series by therotary filter 124 and is radiated onto the observed position through thelight guide 114. The returning light from this observed position is madeto form an image on the above mentioned CCD 170 fitted with anelectronic shutter by the objective lens system 115.

Here, the driver circuit 178 driving the above mentioned CCd fitted withan electronic shutter operates as shown in FIGS. 37 and 38. The drawingshows an example that the video images of the respective wavelengthranges of G, IR2 and UV2 are quasicolored.

The same as in the eighth embodiment, as shown in FIG. 38(A), the lightemitted from the lamp 121 is color-separated into the respectivewavelength ranges of R, G, B, IR1, IR2, IR3, UV1 and UV2 by the rotaryfilter 124 and is radiated onto the observed position through the lightguide 114. The returning light from this observed position is made toform an image on the above mentioned CCd 170 fitted with an electronicshutter. When quasi-coloring the video images of G, IR2 and UV1 asdescribed above, first, as shown by (A) in FIG. 38(B), just before therequired illumination by the G filter is made, as shown in FIG. 38(C),the video signal by the illuminating light accumulated by then in thelight receiving parts 171 and transmitted through the other filters willbe vertically read out of the light receiving parts 171 into thevertically reading-out register 172 as an unnecessary charge as shown inFIG. 37(A). This shall be temporarily called an (A) mode. Then, in FIG.38(B), by a predetermined time in the illumination by the G filterindicated by (B) in FIG. 38(B), the above mentioned verticallyreading-out register 172 will transfer the unnecessary charge to thecharge absorbing drain 176. On the other hand, in the above mentioned(A) mode, the light receiving part 171 having read out the unnecessarycharge will accumulate the video information by the illuminating lighttransmitted through the necessary G filter. Then, the signal chargeaccumulated in the above mentioned high receiving part 171 will be readout into the vertically reading-out register 172 and will be accumulatedin the accumulating part 174. When the signal charge is transferred tothe accumulating part 174 for the imaging part 173 as shown in FIG.37(C) by a predetermined time indicated by (C) in FIG. 38(C), the signalwill be read out as a video image by the illuminating light transmittedthrough the G filter by the horizontally reading-out register 175.

In the same manner, also in the case of the IR2 filter, the unnecessarycharge by the illuminating lights transmitted through the B filter andIR1 filter will be read out and will be absorbed by the charge absorbingdrain 176. On the other hand, since just after the unnecessary charge isread out, the signal charge by IR2 will be accumulated in the lightreceiving part 71, will be read out and transferred the same as in thecase of the above mentioned G filter and will be read out as a videoimage by IR2 by the horizontally reading-out register 175.

The case of the UV2 filter is also the same.

The video signals corresponding to the illuminating lights transmittedthrough the respective filters B, IR2 and UV1 and thus read otu in timeseries are processed the same as in the eighth embodiment and are outputas quasi-colored video images.

When a combination of other filters is selected, the driving pattern ofthe driver circuit 178 will be varied by the switching circuit 143 andthe video signal will be output with any combination.

According to this embodiment, since there is no shutter part in front ofthe solid state imaging device and the device itself functions as ashutter, the tip part 9 of the electronic endoscope can be made small.Further, since there is no mechanical movable part as in the ninthembodiment, the size can be made small and the reliability can beelevated.

The eleventh embodiment of the present invention is shown in FIG. 39.

In this embodiment, the imaging apparatus of the tenth embodiment isapplied to an externally fitted television camera fitted to the eyepiecepart of a fiberscope.

The fiberscope 60 is of the same formation as is shown in the fifthembodiment and therefore its explanation shall be omitted.

An externally fitted television camera 180 is to be removably fitted tothe eyepiece part 65 of the above mentioned fiberscope 60. Thisexternally fitted television camera 180 is provided with an imageforming lens 181 making the light from the above mentioned eyepiece part65 from an image and a CCd 170 fitted with an electronic shutter andarranged in the image forming position of this image forming lens 181.The same as in the tenth embodiment, this CCD 170 fitted with anelectronic shutter is driven by the driver circuit 178 within thecontrol apparatus 6 and the signal read out is inptu into apre-amplifier 132 and is processed the same as in the tenth embodiment.

The other formations, operations and effects are the same as in thetenth embodiment.

In this embodiment, the externally fitted television camera 180 fittedto the eyepiece part 65 of the fiberscope 60 is provided with the CCD170 fitted with an electronic shutter as in the tenth embodiment but maybe provided with the liquid crystal shutter 117 as in the eighthembodiment or may be provided with the shutter 160 using a piezoelctricdevice as in the ninth embodiment.

The twelfth embodiment of the present invention is shown in FIGS. 40 to44.

In this embodiment, the light source is to emit lights ranging from thevisible light range to the infrared light range. A band limiting filter227 as a band limiting means is provided instead of the band switchingfilter 27 in the first embodiment and a rotary filter 231 is providedinstead of the rotary filter 23.

The above mentioned band limiting filter 227 is divided into two partsas shown in FIG. 41 and a filter 227a tranmitting the visible band and afilter 227b transmitting the infrared band as shown in FIG. 42 arearranged in the divided respective parts.Therefore, the light emittedfrom the above mentioned light source 24 will have either of the visibleband and infrared band transmitted depending on the position of thisband limiting filter 227.

On the other hand, the above mentioned rotary filter 231 is divided intothree parts in the peripheral direction as shown in FIG. 43. Filters231a, 231b and 231c are provided repsectively in the divided parts. Inthis embodiment, the above mentioned respective filters have a doubletransmitting characteristic. As shown in FIG. 44, the filter 231atransmits R in the visible band and the infrared band IR, the filter231b transmits G in the visible band and the infrared band IR and thefilter 231c transmits B in the visible band and the infrared band IR.

The other formations are the same as in the first embodiment.

In this embodiment, the transmitted wavelength ranges of the respectivefilters of the above mentioned filter 231 are limited to wavelengthranges belonging to either of the visible band and infrared band by theabove mentioned band limiting filter 227. That is to say, when thevisible band is selected by the above mentioned band limiting filter227, only the visible light will enter the rotary filter 231 andtherefore the lights of R, G and B will be color-separated in timeseries by the above mentioned rotary filter 231 and will enter theentrance end of the light guide 33. On the other hand, when the infraredband is selected by the above mentioned band limiting filter 227, onlythe infrared light will enter the rotary filter 231, the above mentionedrotary filter 231 will not color-separate R, G and B and the light ofthe infrared band IR will be emitted from this rotary filter 231 andwill enter the entrance end of the light guide 33.

In ease the visible band is selected by the above mentioned bandlimiting filter 227, the light of the respective wavelength ranges of R,G and B will be radiated in time series onto the observed object and thereturning light from this observed object will be made to form an imageon the solid state imaging device 36 by the objective lens system 35.This solid state imaging device 36 is driven by the driver 37. Thesignals read out of the solid state imaging device 36 in response to therespective wavelength ranges are to the respective colors of red, greenand blue and are processed to be video signals in the video signalprocessing part 41. For example, the output signal of the abovementioned solid state imaging device 36 is amplified and γ-corrected inthe process circuit 38 and the color signal is corrected in the matrixcircuit 39 so as to reproduce the colors accurately in the colormeasurement. Further, the three kinds of picture images color-separatedin the respective wavelength ranges are temporarily stored in theencoder 40, are converted to video signals observable with a generaltelevision monitor and are output in the monitor 7. Therefore, when therespective colors of red, green and blue are alloted to the respectivewavelength ranges of R, G and B, an ordinary color picture image will beobtained.

On the other hand, when the infrared band is selected by the abovementioned band limiting filter 227, irrespective of the position of therotary filter 231, the light of the infrared band IR will be radiatedonto the observed object and the observed object image in the infraredband will be monocolor-displayed.

Thus, according to this embodiment, the color picture image in thevisible range and the picture image in the infrared range can beswitched over to each other and the disease and vein running state belowthe mucous membrane so far difficult to detect with only the visiblelight can be confirmed and the diagnosing activity can be improved.

The respective filters 231a, 231b and 231c of the above mentioned rotaryfilter 231 not only transmit respective R, G and B in the visible bandas shown in FIG. 44 but also may transmit respectively yellow (Ye),green (G) and cyanine (Cy) in the visible band as shown, for example, inFIG. 45.

The above mentioned band limiting filter 227 is not limited to bedisc-like as shown, for example, in FIG. 41 but also, as shown, forexample, in FIG. 46, a filter 228a transmitting the visible band and afilter 228b transmitting the infrared band are arranged in theperipheral direction in a substantially fan-shaped frame 228 so that,when the frame 228 is rotated by a predetermined angle with the rotaryshaft 229 as a center, either of the filters 228a and 228b mayselectively interposed in the illuminating light path of the lightsource 24. Also, as shown in FIG. 47, the filter 231a transmitting thevisible band and the filter 231b transmitting the infrared band arearranged on the left and right in the frame 231 so that, when the abovementioned frame 231 is moved in the rightward and leftward direction bya rack 232 provided in the rightward and leftward direction in the abovementioned frame 231 and a pinion 233 meshing with this rack 232, theabove mentioned frame 231 may be moved in the rightward and leftwarddirection and thereby either of the filters 231a and 231b may beselectively interposed in the illuminating light path of the lightsource 24.

The thirteenth embodiment of the present invention is shown in FIGS. 48to 50.

In this embodiment, a band limiting filter 240 is provided insertably inthe illuminating light path of the light source 24 in the light sourcepart 22 in the twelfth embodiment. The above mentioned band limitingfilter 240 has a band pass characteristic of a narrow band having 805nm. in the center as shown in FIG. 49. The transmitted wavelength bandWo of this band limiting filter 240 is so narrow as to be preferablyless than about 40 nm.

The other formations are the same as in the twelfth embodiment.

FIG. 50 shows a difference in the spectral characteristic (theattenuation rate by mixing in ICG) between blood in which was mixedIndocyanine green (ICG) which is an infrared ray absorbing color andblood in which ICG was not mixed. As shown in this diagram, the blood inwhich ICG was mixed has a maximum absorption at 805 nm. Therefore, whenICG is mixed into blood, for example, by venous injection and theinfrared band is selected by the band limiting filter 227 and the abovementioned band limiting filter 240 having a band pass characteristic inwhich the absorption factor has a maximum of 805 nm. in the center isinterposed in the illuminating light path, a light of a narrow bandhaving 805 nm. in the center will be radiated onto the observed objectand the observed object image in this narrow band will be observed. Thelight having 805 nm. in the center will reach the deep part of themucous membrane and will be absorbed in the venous part and thereforethe venous part will be observed as a shadow. Therefore, as comparedwith the observation in other wavelength ranges, the vein running statecan be observed in a much higher contrast.

The operation when the above mentioned band limiting filter 240 isretreated from the illuminating light path of the light source 24 is thesame as in the twelfth embodiment. It is needless to say that the rotaryfilter 231 may have a transmitting characteristic as is shown in FIG.45.

A light source 241 as a laser or LED emitting a light of a narrow bandhaving 805 nm. in the center as shown in FIG. 51 may be prepared insteadof inserting the above mentioned band limiting filter 240 in theilluminating light path and may be used instead of the light source 24emitting a light of a wide band in the case of observing the observedobject image in the narrow band having 805 nm. in the center.

The fourteenth embodiment of the present invention is shown in FIG. 52.

In this embodiment, the transmitting characteristics of the respectivefilters 231a, 231b and 231c of the rotary filter 231 in the twelfthembodiment are so made that, as shown in FIG. 52, the filter 231a maytransmit R in the visible band and the narrow band having 805 nm. in thecenter, the filter 231b may transmit G in the visible band and thenarrow band having 805 nm. in the center and the filter 231c maytransmit B in the visible band and the narrow band having 805 nm. in thecenter.

The other formations are the same as in the twelfth embodiment.

In this embodiment, when the visible band is selected by the bandlimiting filter 227, a color picture image by an ordinary visible bandwill be obtained. On the other hand, when the infrared band is selectedby the above mentioned band limiting filter 227, only a light of thenarrow band having 805 nm. in the center will be transmitted through theabove mentioned rotary filter 231 and will be radiated onto the observedobject and the observed object image in this narrow band will beobserved.

The filters transmitting the narrow band having 805 nm. in the centerneed not be all of the filters 231a, 231b and 231c. For example, onefilter may be made to have the above mentioned narrow band transmittingcharacteristic. In this case, when the rotary filter 231 is stopped inthe position in which the filter transmitting this narrow band isinterposed in the illuminating light path and the visible band isselected by the band limiting filter 227, the observed object image inthe narrow band having 805 nm. in the center will be observed. Thus,even if only one filter is made to have the above mentioned narrow bandtransmitting characteristic, in the case of imaging in a fieldsequential system, the resolution will not reduce.

The fifteenth embodiment of the present invention is shown in FIGS. 53and 54.

In this embodiment, a rotary filter 251 is provided instead of therotary filter 231 in the twelfth embodiment.

As shown in FIG. 53, the above mentioned rotary filter 251 is dividedinto three parts and filters 251a, 251b and 251c are arranged in thedivided respective parts. The respective filters 251a, 251b and 251chave a double transmitting characteristic. As shown in FIG. 54, thefilter 251a transmits R in the visible band and IR3 in the infraredband, the filter 231b transmits G in the visible band and IR2 in theinfrared band and the filter 231c transmits B in the visible band andIR1 in the infrared band.

The other formations are the same as in the twelfth embodiment.

In this embodiment, when the visible band is selected by the bandlimiting filter 227, the same as in the twelfth embodiment, the light ofR, G and B will be color-separated in time series by the rotary filter251 and a color picture image in an ordinary visible band will beobtained. On the other hand, when the infrared band is selected by theabove mentioned band limiting filter 227, the light of IR1, IR2 and IR2will be color-separated in time series by the above mentioned rotaryfilter 251 and three lights will be radiated onto the observed object.In the video signal processing part 41, the respective colors of red,green and blue are optionally alloted to the above mentioned wavelengthranges of IR1, IR2 and IR3 and the video signals are processed.Therefore, the observed object image of the infrared band is displayedin quasi colors.

According to this embodiment, the observed object image in the infraredband can be color-displayed and therefore the color tone difference inthe respective positions of the observed object in the infrared band canbe easily detected.

The sixteenth embodiment of the present invention is shown in FIGS. 55to 58.

In this embodiment, the light source 24 is to emit light ranging fromthe visible light range to the ultraviolet light range. A band limitingfilter 261 is provided instead of the band limiting filter 227 in thetwelfth embodiment. A rotary filter 262 is provided instead of therotary filter 231.

As shown in FIG. 55, the above mentioned band limiting filter 261 isdivided into two parts in the peripheral direction. As shown in FIG. 56,a filter 261a transmitting the visible band and a filter 261btransmitting the ultraviolet band are arranged in the divided respectiveparts. Therefore, depending on the position of this band limiting filter261, of the light emitted from the above mentioned light source 24,either of the visible band and ultraviolet band will be selectivelytransmitted.

On the other hand, as shown in FIG. 57, the above mentioned rotaryfilter 262 is divided into three parts in the peripheral direction andfilters 262a, 262b and 262c are arranged in the divided respectiveparts. In this embodiment, the above mentioned respective filters 262a,262b and 262c have a double transmitting characteristic. As shown inFIG. 58, the filter 262a transmits R in the visible band and UV3 in theultraviolet band, the filter 262b transmits G in the visible band andUV2 in the ultraviolet band and the filter 262c transmits B in thevisible band and UV1 in the infrared band.

The other formations are the same as in the twelfth embodiment.

In this embodiment, when the visible band is selected by the bandlimiting filter 261, the same as in the twelfth embodiment, the light ofR, G and B will be color-separated in time series by the rotary filter262 and a color picture image in an ordinary visible range will beobtained. On the other hand, when the ultraviolet band is selected bythe above mentioned band limiting filter 261, the light of UV1, UV2 andUV3 will be color-separated in time series by the above mentioned rotaryfilter 262 and will be radiated onto the observed object. In the videosignal processing part 41, the respective colors of red, green and blueare optionally alloted to the above mentioned wavelength ranges of UV1,UV2 and UV3 to process video signals. Therefore, the observed objectimage in the ultraviolet band is displayed in quasi colors.

According to this embodiment, as the observed object image not only inthe visible band but also in the ultraviolet band can becolor-displayed, the color tone difference in the respective positionsof the observed object in the ultraviolet band can be easily detected.

The seventeenth embodiment of the present invention is shown in FIG. 59.

In this embodiment, the imaging apparatus of the twelfth embodiment isapplied to an externally fitted television camera fitted to the eyepiecepart of a fiberscope.

The fiberscope 60 is of the same formation as is shown in the fifth andeleventh embodiments and its explanation shall be omitted.

An externally fitted television camera 270 is to be removably fitted tothe eyepiece part 65 of the above mentioned fiberscope 60. Thisexternally fitted television camera 270 is provided with an imageforming lens 271 forming an image of the light from the above mentionedeyepiece part 65 and a solid state imaging device arranged in the imageforming position of this image forming lens 271. The light emitted fromthe light source 24 is to enter the entrance end of the light guide 69of the fiberscope 60 through the band limiting filter 117 and rotaryfilter 231.

The other formations, operations and effect are the same as in thetwelfth embodiment.

In this embodiment, the combination of the rotary filter and bandlimiting filter is not limited to be such as is shown in the twelfthembodiment but may be such as is shown in the thirteenth to sixteenthembodiments.

In the above mentioned twelfth to seventeenth embodiments, there may beused a band limiting filter which can selectively transmit such three ormore bands as the ultraviolet band, visible band and infrared band andrespective filters of the color filter having a transmittingcharacteristic in three or more ranges selectable by the above mentionedband limiting filter so that any observing wavelength band may beselected from among three or more observing wavelength bands.

The selectable observing wavelength band is not limited to be dividedinto ultraviolet, visible and infrared bands but may be set so that, forexample, a part of the long wavelength side of the visible range and theshort wavelength side of the infrared range may be made an observingwavelength band.

The band limiting filter and rotary filter 37 may be arranged betweenthe light source 24 and an imaging means such as the solid state imagingdevice 36 and the arranging order can be optionally determined.

Not only the light reflected by the observed object but also the lighttransmitted through the observed object may be received.

The eighteenth embodiment of the present invention is shown in FIGS. 60to 65.

The imaging apparatus of this embodiment is formed as shown in FIG. 60.

A light source 24 is provided within the control apparatus 6. As shownin FIG. 61, this light source 24 is to emit a light of a wavelength in awide band at least ranging from the visible range to the infrared rangeand can be a general halogen lamp, xenone lamp or the like. This lightsource 24 is controlled to be lighted by a light source lightingapparatus 26 controlled by the control part 25. A band limiting filter328 as a band limiting means rotated and driven by a driving motor 327is arranged in front of the above mentioned light source 24 and isdivided into two parts in the peripheral direction as shown in FIG. 62.A filter 328a transmitting the visible band and a filter 328btransmitting the infrared band are arranged in the divided respectiveparts as shown in FIG. 63. Therefore, of the light emitted from theabove mentioned light source 24, either of the visible band and infraredband is selectively transmitted by this band limiting filter 328. Theabove mentioned driving motor 327 is controlled to rotate by the motordriver 29 controlled by the control part 25.

The light transmitted through the above mentioned band limiting filter328 enters the light guide 33 inserted through the above mentioned cable4 and insertable part 2, is led to the tip part 9 through this lightguide 33 and is emitted from the light distributing lens 34 provided inthis tip part 9 to illuminate the observed object.

On the other hand, a solid state imaging device 336 as an imaging meansis arranged in the image forming position of the objective lens system35 provided in the tip part. This solid state imaging device 336 has asensitivity at least to the visible band and infrared band. A colorfilter 337 as a wavelength range dividing means is arranged in front ofthe imaging surface of the above mentioned solid state imaging device336. In this color filter 337, as shown in FIG. 64, filters 337a, 337band 337c transmitting respectively different wavelength ranges arearranged, for example, to be mosaic-like.

In this embodiment, the above mentioned respective filters 337a, 337band 337c have a double transmitting characteristic and have transmittedwavelength ranges in the visible band and infrared band. That is to say,as shown in FIG. 65, the filter 337a transmits the red light R in thevisible band and infrared light IR3 in the infrared band, the filter337b transmits the green light G in the visible band and infrared lightIR2 in the infrared band and the filter 337c transmits the blue light Bin the visible band and infrared light IR1 in the infrared band. Theabove mentioned infrared lights IR1, IR2 and IR3 are respectivelydifferent in the wavelength range and the center wavelengths are longerin the order of IR1, IR2 and IR3.

In this embodiment, the transmitted wavelength ranges of the respectivefilters 337a, 337b and 337c of the above mentioned color filter 337 arelimited to the wavelength ranges belonging to either of the visible bandand infrared band by the above mentioned band limiting filter 328. Thatis to say, when the visible band is selected by the above mentioned bandlimiting filter 328, the infrared band will not be illuminated andtherefore the respective filters 337a, 337b and 337c of the abovementioned color filter 337 will transmit respectively B, G and R of thevisible band. On the other hand, when the infrared band is selected bythe above mentioned band limiting filter 328, the visible band will notbe illuminated and therefore the respective filters 337a, 337b and 337cof the above mentioned color filter 337 will transmit respectively IR1,IR2 and IR3 in the infrared band. The light transmitted through theabove mentioned respective filters 337a, 337b and 337c are received bythe above mentioned solid state imaging device 336 and arephotoelectrically converted. The signals corresponding to the respectivepicture elements of this solid state imaging device 336 are input into avideo signal processing part 338 and are processed in response to asimultaneous system. In this video signal processing part 338, thesignals corresponding to the respective picture elements of the abovementioned solid state imaging device 336 are processed to be videosignals by the type of the filters 337a, 337b and 337c in front of therespective picture elements. For example, red(R) is alloted to thepicture element signal corresponding to the filter 337a, green(G) isalloted to the picture element signal corresponding to the filter 337band blue(B) is alloted to the picture element signal corresponding tothe filter 337c and the signals are processed to be video signals. Thevideo signals output from this video signal processing part 338 areinput into the above mentioned color CRT monitor 7 and the observedobject is color-displayed.

In this embodiment formed as in the above, when the light sourcelighting device 26 is operated to be lit by the control part 25, a lightincluding a visible light and infrared light will be emitted from thelight source 24. Of the light emitted from this light source 24, onlythe visible band or infrared band is selectively transmitted by the bandlimiting filter 228. The light having passed through this band limitingfilter 228 is radiated onto the observed object.

The reflected light of the observed object corresponding to thisilluminating light is received by the solid state imaging device 336through the color filter 337 arranged in front of the solid stateimaging device. The respective filters 337a, 337b and 337c of the abovementioned color filter 337 have a transmitted wavelength range in thevisible band and infrared band so that, when the visible band isselected by the above mentioned band limiting filter 328, the respectivefilters 337a, 337b and 337c of the above mentioned color filter 337 willtransmit respectively B, G and R of the visible band but, on the otherhand, when the infrared band is selected by the above mentioned bandlimiting filter 328, the respective filters 337a, 337b and 337c of theabove mentioned color filter 337 will transmit respectively IR1, IR2 andIR3 of the infrared band.

The light having entered the above mentioned solid state imaging device336 is photoelectrically converted and is processed in the video signalprocessing part 338 to produce video signals and the observed objectimage is color-displayed by the color CRT monitor That is to say, whenthe visible band is selected by the band limiting filter 328, a generalvisible range image of the observed object will be displayed but, on theother hand, when the infrared band is selected by the band limitingfilter 328, an infrared range image of the observed object will bedisplayed in quasi colors.

Thus, according to this embodiment, by switching the band limitingfilter 328, the observing band of either of the visible range andinfrared range is selected in response to the observed object which canbe color-displayed. Therefore, an optimum observing wavelength range canbe selected in response to the observed object. The color tonedifference in the respective positions of the observed object difficultto discriminate in the picture image of the general visible range can beeasily detected.

The respective filters 337a, 337b and 337c of the above mentioned colorfilter 337 are not limited to transmit respectively R, G and B in thevisible band as shown in FIG. 64 but may transmit respectivelyyellow(Ye), green(G) and cyanine(Cy) in the visible band.

The nineteenth embodiment of the present invention is shown in FIG. 66.

The respective filters 337a, 337b and 337c of the color filter 337 inthis embodiment are to transmit respectively the red light R andinfrared band IR, the green light G and infrared band IR and the bluelight B and infrared band IR as shown in FIG. 65.

In the video processing part 338, when the visible band is selected bythe band limiting filter 328, the output signal of the solid stateimaging device 336 will be processed as a color picture image to be avideo signal but, on the other hand, when the infrared band is selectedby the above mentioned band limiting filter 328, the output signal ofthe above mentioned solid state imaging device 336 will be processed asa monocolor picture image to be a video signal. The other formations arethe same as in the eighth embodiment.

In this embodiment, by switching the band limiting filter 328, the colorpicture image in the visible band and monocolor picture image in theinfrared band can be selectively displayed in response to the observedobject.

In this embodiment, as compared with the color filter of thetransmitting characteristic shown in FIG. 65, the respective filters337a, 337b and 337c of the color filter 337 will be more easily formedand the lower cost can be realized.

The respective filters 337a, 337b and 337c of the above mentioned colorfilter 337 are not limited to transmit respectively R, G and B in thevisible band as shown in FIG. 66 but may transmit yellow(Ye), green(G)and cyanine(Cy) in the visible band as shown, for example, in FIG. 45.

The twentieth embodiment of the present invention is shown in FIG. 67.

In this embodiment, a band limiting filter 340 is provided insertably inthe illuminating light path of the light source 24 in the nineteenthembodiment and has a band pass characteristic of a narrow band having805 nm. in the center as shown in FIG. 49. It is preferable that thetransmitted wavelength band Wo of this band limiting filter 240 is sonarrow as to be less than about 40 nm.

The other formations are the same as in the nineteenth embodiment.

As shown in FIG. 50, the blood in which ICG is mixed has a maximumabsorption at 805 nm. Therefore, when ICG is mixed in blood, forexample, by venous injection, the infrared band is selected by the bandlimiting filter 328 and the above mentioned band limiting filter 340having a band pass characteristic having a maximum absorption factor of805 nm. in the center is interposed in the illuminating light path ofthe light source 24, the light of the narrow band having 805 nm. in thecenter will be radiated onto the observed body and the observed bodyimage in this narrow band will be observed. The light having 805 nm. inthe center will reach the deep part of the mucous membrane, absorptionwill be made in the vein part and therefore the vein part will beobserved as a shadow. Therefore, as compared with the case of observingin other wavelength ranges, the vein running state can be observed in amuch higher contrast.

The operation when the above mentioned band limiting filter 340 isretreated from the illuminating light path of the light source 24 is thesame as in the eighteenth embodiment. The color filter 337 is notlimited to be as shown in FIG. 66 but may have a transmittingcharacteristic shown, for example, in FIG. 45.

As shown in FIG. 68, a light source 341 such as a laser or LED emittingthe light of a narrow band having 805 nm. in the center may be preparedinstead of inserting the above mentioned band limiting filter 340 in theilluminating light path. When observing the observed object image in thenarrow band having 805 nm. in the center, the above mentioned lightsource 341 may be used instead of the light source 24 emitting the lightof a wide band.

The twenty-first embodiment of the present invention is shown in FIG.69.

In this embodiment, the transmitting characteristics of the respectivefilters 337a, 337b and 337c of the color filter 337 in the nineteenthembodiment are so made that, as shown in FIG. 69, the filter 337atransmits R in the visible band and the narrow band having 805 nm. inthe center, the filter 337b transmits G in the visible band and thenarrow band having 805 nm. in the center and the filter 337c transmits Bin the visible band and the narrow band having 805 nm. in the center.

The other formations are the same as in the nineteenth embodiment.

In this embodiment, when the visible band is selected by the bandlimiting filter 328, a color picture image by an ordinary visible bandwill be obtained but, on the other hand, when the infrared band isselected by the above mentioned band limiting filter 328, the infraredlight will be radiated onto the observed object, only the light of thenarrow band having 805 nm. in the center will pass through the abovementioned color filter 337 and the observed object image in this narrowband will be observed.

The filters transmitting the narrow band having 805 nm. in the centerneed not be all of the filters 337a, 337b and 337c but, for example, onefilter may have the above mentioned narrow band transmittingcharacteristic.

The twenty-second embodiment of the present invention is shown in FIGS.70 to 72.

In this embodiment, a band limiting filter 351 as is shown in FIG. 70 isprovided instead of the band limiting filter in the eighteenthembodiment.

The respective filters 351a and 351b of this band limiting filter 351are filters transmitting respectively the visible band and ultravioletband as shown in FIG. 71. The respective filters 337a, 337b and 337c ofthe color filter 337 have the transmitted wavelength range in thevisible band and ultraviolet band as shown in FIG. 72. That is to say,the filter 337a transmits the red light R and the ultraviolet light UV3in the ultraviolet band, the filter 337b transmits the green light G andthe ultraviolet light UV2 in the ultraviolet band and the filter 337ctransmits the blue light B and the ultraviolet light UV1. The abovementioned ultraviolet light UV2, UV2 and UV3 are respectively differentin the wavelength range and are longer in the center wavelength in theorder of UV1, UV2 and UV3.

In this embodiment, by switching the band limiting filter 351, either ofthe visible band and ultraviolet band is selected in response to theobserved object which can be color-displayed. Therefore, the color tonedifference in the respective positions of the observed object in theultraviolet band which has not been able to be observed in the pictureimage of the general visible range can be observed.

The twenty-third embodiment of the present invention is shown in FIG.73.

In this embodiment, the imaging apparatus of the eighteenth embodimentis applied to an externally fitted television camera fitted to theeyepiece part of a fiberscope.

The fiberscope 60 is of the same formation as is shown in the fifth,eleventh and seventeenth embodiments and therefore its explanation shallbe omitted.

An externally fitted television camera 370 is removably fitted to theeyepiece part 65 of the above mentioned fiberscope 60 and is providedwith an image forming lens 371 forming an image of the light from theabove mentioned eyepiece part 65 and a solid state imaging device 336arranged in the image forming position of this image forming lens 371.The color filter 337 having a transmitting characteristic for thevisible band and infrared band is provided in front of this solid stateimaging device 336 the same as in the eighteenth embodiment. The lightemitted from the light source 24 passes through the band limiting filter328 transmitting selectively the visible band and infrared band andenters the entrance end of the light guide 69 of the fiberscope 60.

The other formations, operations and effects are the same as in theeighteenth embodiment.

In this embodiment, the combination of the color filter and bandlimiting filter is not limited to be as shown in the eighteenthembodiment but may be as shown in the eighteenth to twenty-thirdembodiments.

In the above mentioned eighteenth to twenty-third embodiments, the bandlimiting filter which can transmit selectively more than three as theultraviolet band, visible band and infrared band may be used and therespective filters 337a, 337b and 337c of the color filter 337 havingtransmitted wavelength ranges in more than three bands which can beselected by the above mentioned band limiting filter may be used so thatany observed wavelength band can be selected from among more than threeobserved wavelength bands.

The selectable observed wavelength band is not limited to be dividedinto the ultraviolet, visible and infrared bands but may be set to be,for example, a part of the long wavelength side of the visible range andthe short wavelength side of the infrared range.

Further, the band limiting filter and color filter may be arrangedbetween the light source 24 and an imaging means such as the solid stateimaging device 336 and the arranging order can be optionally determined.

The twenty-fourth embodiment of the present invention is shown in FIGS.74 to 79.

In this embodiment, a lamp 407 fed with an electric power by a currentsource 406 is provided within the control apparatus 6. This lamp 407 isto emit a light of a wavelength in a wide band ranging from a visiblerange to an infrared range. A visible light transmitting filter 421 andnear infrared band pass filter 422 respectively individually insertablein an illuminating light path by a filter changer 423 are providedbetween the above mentioned lamp 407 and the entrance end of the lightguide of the electronic endoscope 1. The above mentioned visible lighttransmitting filter 421 has a transmitting characteristic oftransmitting a visible light range as shown in FIG. 78 and the abovementioned near infrared band pass filter 422 has a transmittingcharacteristic of transmitting only a near infrared light as shown inFIG. 79. The above mentioned filter changer 423 is controlled by acontrol circuit 420.

On the other hand, an objective lens system 401 is provided in the tippart 9 of the electronic endoscope 1. A solid state imaging device 404is arranged in the image forming position of this objective lens system.This solid state imaging device 404 has a sensitivity at least to avisible to near infrared light range. A color separating filter 403 isprovided on the front surface of the above mentioned solid state imagingdevice 404. As shown in FIG. 75, this color separating filter 403 isformed by arranging in a mosaic form respective color filters 403a, 403band 403c transmitting respectively cyanine(Cy), green(G) and yellow(Ye)in the visible band. The respective filters 403a, 403b and 403c of theabove mentioned color separating filter 403 have a double transmittingcharacteristic of transmitting not only Cy, G and Ye in the visible bandbut also an infrared light as shown in FIG. 76.

A filter 402 having a characteristic of transmitting a visible band anda narrow band having 805 nm. in the center as shown in FIG. 77 isprovided between the above mentioned lens system 401 and solid stateimaging device 404.

The above mentioned solid state imaging device 404 is driven by a driver410 within the control apparatus and the signal read out is amplified bya pre-amplifier 411, is then input into a process circuit 412 and isprocessed to be γ-corrected, white-balanced and matrix-processed. Thevideo signal from this process circuit 412 is input into an NTSC encoder413, is converted to a video signal of an NTSC system and is input intothe monitor 7.

The above mentioned control circuit 420, driver 410, process circuit 412and NTSC encoder 413 are synchronized by a timing generator 414generating the synchronized signal of the entire system.

In this embodiment, a light in a visible to infrared light range isemitted from the lamp 407 by an electric power from the current source406, is transmitted to the tip part 9 of the electronic endoscope 1through the light guide 33 and is radiated onto an object to be imaged.The returning light from the object by this illuminating light is madeto form an image on the solid state imaging device 404 by the objectivelens system and the object is imaged by this solid state imaging device404.

Here, if only the visible light transmitting filter 421 is interposed inthe illuminating light path by driving the filter changer 423 with thecontrol by the control circuit 420, the light emitted from the abovementioned lamp 407 will pass through this visible light transmittingfilter 421 to be made a visible light which will be radiated onto theobject to be imaged. The returning light from the object by thisilluminating light passes through the filter 402, is separated intocolors by the color separating filter 403 and is then read out as avideo signal by the solid state imaging device 404. The output signal ofthis solid state imaging device 404 is processed by the pre-amplifier411, process circuit 412 and NTSC encoder 413 and a visible pictureimage is color-displayed in the monitor 7.

On the other hand, if only the near infrared band pass filter 422 isinterposed in the illuminating light path by driving the filter changer423 with the control by the above mentioned control circuit, the lightemitted from the above mentioned lamp 407 will pass through this nearinfrared band pass filter 422 to be made a near infrared light whichwill be radiated onto the object to be imaged. The returning light fromthe object by this illuminating light enters the filter 402 and only thelight in a narrow band having 805 nm. in the center passes through thisfilter 402. The light of this narrow band passes through the colorseparating filter 403 without being separated into colors by thisseparating filter and is read out as a video signal by the solid stateimaging device 404. The output signal of this solid state imaging device404 is processed by the pre-amplifier 11, process circuit 412 and NTSCencoder 413. The object image in the narrow band having 805 nm. in thecenter is displayed as a monocolor image in the monitor.

Thus, according to this embodiment, the same as in the otherembodiments, not only an ordinary visible color picture image isobtained but also an infrared picture image in a narrow band having 805nm. in the center can be obtained. Therefore, the same as in the ninthand sixteenth embodiments, by observing the infrared picture image inthe narrow band having 805 nm. in the center by mixing ICG into blood,the veins running below the mucous membrane and the range of a diseasein the deep part of the membrane which have been difficult or impossibleto observe can be observed. Further, in the case of processing with aYAG laser, there is also an effect that, when the filter 402 having atransmitting characteristic of transmitting only the near infrared lighthaving 805 nm. in the center in the infrared light range is provided infront of the solid state imaging device 404, the observed picture planewill not be disturbed by the light of 1060 nm. of the YAG laser.

The twenty-fifth embodiment of the present invention is shown in FIGS.80 to 82.

The imaging apparatus of this embodiment is of substantially the sameformation as of the eighth embodiment shown in FIG. 26 and the tenthembodiment shown in FIG. 35 but shutters such as the liquid crystalshutter 117 and electronic shutter are not provided.

As shown in FIG. 80, the objective lens system 115 is provided in thetip part of the electronic endoscope 1 and a solid state imaging device452 is arranged in the image forming position of this objective lenssystem 115. This solid state imaging device 452 has a sensitivity to awide wavelength range from an ultraviolet range to an infrared range andincluding a visible range. Signal lines 126 and 127 are connected to theabove mentioned solid state imaging device 452, are inserted through theabove mentioned insertable part 2 and universal cord and are connectedto the connector 5.

On the other hand, a lamp 121 emitting a light in a wide band from anultraviolet light to an infrared light is provided within the controlapparatus. A rotary filter 450 rotated and driven by a motor 123 isarranged in front of the above mentioned lamp 121. In this rotary filter450, as shown in FIG. 81, filters 450a, 450b and 450c transmittingrespectively R, G and B are arranged in the peripheral direction on theouter peripheral side and a filter 450d transmitting an ultravioletrange UV1, a filter 450e having a band pass characteristic of a narrowband IR1 having 805 nm. in the center and a filter 450f transmitting aninfrared light IR2 of more than 900 nm. are arranged in the peripheraldirection on the inner peripheral side. The transmitting characteristicsof the above mentioned respective filters 450a to 450f are shown in FIG.82.

In this embodiment, a filter switching device 451 is provided and ismade to move the above mentioned rotary filter 450 and motor 123 so thateither of the outer peripheral side and inner peripheral side of theabove mentioned rotary filter 450 may be interposed in the illuminatinglight path between the lamp 121 and the entrance end of the light guide114.

The light having passed through the above mentioned rotary filter 450enters the entrance end of the above mentioned light guide 114, is ledto the tip part 9 through the light guide 114 and is emitted from thistip part 9 to illuminate the observed position.

The returning light from the observed position by this illuminatinglight is made to form an image on the solid state imaging device 452 bythe objective lens system 115 and is photoelectrically converted. Adriving pulse from the driver circuit 178 within the above mentionedcontrol apparatus 6 is applied to the solid state imaging device 452through the above mentioned signal line 126 and the signal is read outand transferred by this driving pulse. The video signal read out of thissolid state imaging device 452 is input through the above mentionedsignal line 127 into the pre-amplifier 132 provided within the abovementioned control apparatus or within the electronic endoscope 1. Thevideo signal amplified by this preamplifier 132 is processed by theprocess circuit 133, A/D converter 234, selecting circuit 135, threememories (1) 136a, (2) 136b and (3) 136c, D/A converter 137 andconverter 138 the same as in the eighth and tenth embodiments.

The other formations are the same as in the eighth or tenth embodiment.

In this embodiment, when the filter switching device 451 is controlledby the switching circuit 143 to interpose the outer peripheral side ofthe rotary filter 450 into the illuminating light path between the lamp121 and the entrance end of the light guide 114, the light emitted fromthe above mentioned lamp 121 will pass in turn through the filters 450a,450b and 450c transmitting respectively R, G and B of the abovementioned rotary filter 450 and will be divided in time series into thelight of the respective wavelength range of R, G and B. This light of R,G and B is transmitted to the tip part 9 through the light guide 114 andis radiated onto the object to be imaged. The returning light from theobject by the illuminating light in the field order of R, G and B inthis visible range is made to form an image on the solid state imagingdevice 452 by the objective lens system 115 and the object is imaged bythis solid state imaging device 452. Therefore, an ordinary visiblepicture image is color-displayed in the monitor.

On the other hand, when the filter switching device 451 is controlled bythe above mentioned switching circuit 143 to interpose the innerperipheral side of the rotary filter 450 into the illuminating lightpath between the lamp 121 and the entrance end of the light guide 114,the light emitted from the above mentioned lamp 121 will pass in turnthrough the filters 450d, 450e and 450f transmitting respectively UV1,IR1 and IR2 of the above mentioned rotary filter 450 and will be dividedin time series into light of the respective wavelength ranges of UV1,IR1 and IR2. The light is are transmitted to the tip part 9 through thelight guide 114 and is radiated onto the object to be imaged. Thereturning light from the object by this illuminating light is made toform an image on the solid state imaging device 452 by the objectivelens system 115 and the object is imaged by this solid state imagingdevice 452. Therefore, a picture image in invisible ranges such as theultraviolet and infrared light ranges by the respective wavelengthranges of UV1, IR1 and IR2 is displayed in quasi colors in the monitor7. When one or two of the memories 136a, 136b and 136c are selectivelyread out, a picture image by one or two wavelength ranges of UV1, IR1and IR2 will be able to be obtained.

Thus, according to this embodiment, the same as in the otherembodiments, not only an ordinary visible color picture image but also apicture image in invisible ranges such as the ultraviolet and infraredlight ranges can be obtained.

The transmitted wavelength ranges of the respective filters provided onthe outer peripheral side and inner peripheral side of the abovementioned rotary filter 450 are not limited to be as in this embodimentbut can be set freely.

The present invention is not limited to the above mentioned respectiveembodiments. For example, the reflected light from the observed objectis not limited to be received but the light having passed through theobject may be received.

The present invention can be applied to others than the endoscope.

The present invention has effects that visible information can beobtained by selecting an optimum wavelength range in response to theobserved object and the color tone difference in the respectivepositions of the observed object difficult to discriminate in thepicture image in the general visible range can be easily detected.

In this invention, it is apparent that working modes different in a widerange can be formed on the basis of this invention without deviatingfrom the spirit and scope of the invention. This invention is notrestricted by its specific working modes except being limited by theappended claims.

What is claimed is:
 1. An imaging apparatus for observing an objectimage of ordinary light and an object image of particular lightcomprising:an illuminating means for emitting an illuminating light of awavelength range ranging from a visible range to a range other than thevisible range; an image forming optical system for forming the objectimage to be imaged; an imaging means having a sensitivity to awavelength range ranging from the visible range to the range other thanthe visible range and using a solid state imaging device converting animage formed by said image forming optical system to an electric signal;a color filter provided between said image forming optical system andsaid imaging means, said color filter separating said object image intoimages of a plurality of wavelength ranges, said color filter having aplurality of types of component filters, respective component filtershaving a transmitting characteristic of respectively transmitting thelight of specific wavelength ranges within the visible band and the bandother than the visible band; a band dividing means for dividing theilluminating light into said visible band and said band other than thevisible band, said band dividing means for selecting either band toselect the wavelength range imaged by said imaging means and to obtainsaid object image of ordinary light or particular light; and a signalprocessing means for processing output signals of said imaging means inresponse to the wavelength ranges within a band selected by said banddividing means so as to be video signals.
 2. An imaging apparatusaccording to claim 1 wherein said specific wavelength ranges within saidvisible band transmitted by the respective component filters of saidcolor filter are respectively different in said respective componentfilters, said specific wavelength ranges within said band other than thevisible band transmitted by said respective component filters are thesame specific wavelength ranges within the infrared band, said banddividing means include a filter selectively transmitting the visibleband and infrared band.
 3. An imaging apparatus according to claim 2,wherein said band dividing means includes a filter transmitting a narrowband insertable provided in the optical path from said illuminatingmeans to said imaging means.
 4. An imaging apparatus according to claim2 further comprising an illuminating means for emitting a light of anarrow band interchangeably provided with said illuminating means foremitting the illuminating light of the wavelength range ranging from thevisible range to the range other than the visible range.